diff --git a/docs/cookbook/all.do b/docs/cookbook/all.do
index 7d12d02..6bd494d 100644
--- a/docs/cookbook/all.do
+++ b/docs/cookbook/all.do
@@ -1,4 +1,4 @@
 export NO_SLOW_TESTS=1
-for d in */all.do; do
+for d in */all.do */test.do; do
     echo "${d%.do}"
 done | xargs redo-ifchange
diff --git a/docs/cookbook/c/.gitignore b/docs/cookbook/c/.gitignore
new file mode 100644
index 0000000..0703d8b
--- /dev/null
+++ b/docs/cookbook/c/.gitignore
@@ -0,0 +1,6 @@
+hello
+/when.c
+/allconfig
+/arches
+/out
+/out.*
diff --git a/docs/cookbook/c/all.do b/docs/cookbook/c/all.do
new file mode 100644
index 0000000..c359ac3
--- /dev/null
+++ b/docs/cookbook/c/all.do
@@ -0,0 +1 @@
+redo-ifchange all.each
diff --git a/docs/cookbook/c/all.h b/docs/cookbook/c/all.h
new file mode 100644
index 0000000..d5fdaa0
--- /dev/null
+++ b/docs/cookbook/c/all.h
@@ -0,0 +1,4 @@
+#include "main.h"
+#include "libhello/hello.h"
+#include "monotime.h"
+#include <stdio.h>
diff --git a/docs/cookbook/c/all.hpp b/docs/cookbook/c/all.hpp
new file mode 100644
index 0000000..8979800
--- /dev/null
+++ b/docs/cookbook/c/all.hpp
@@ -0,0 +1,4 @@
+#include <algorithm>
+#include <string>
+#include <list>
+#include <map>
diff --git a/docs/cookbook/c/all.od b/docs/cookbook/c/all.od
new file mode 100644
index 0000000..94f4a47
--- /dev/null
+++ b/docs/cookbook/c/all.od
@@ -0,0 +1 @@
+redo-ifchange "hello world"
diff --git a/docs/cookbook/c/all.rc.od b/docs/cookbook/c/all.rc.od
new file mode 100644
index 0000000..179fc92
--- /dev/null
+++ b/docs/cookbook/c/all.rc.od
@@ -0,0 +1,23 @@
+. ./redoconf.rc
+rc_include \
+	rc/CC.rc \
+	rc/CXX.rc \
+	rc/libqt4.rc \
+	rc/libgtk2.rc \
+	rc/Wextra.rc \
+	rc/Wall.rc \
+	rc/libm.rc \
+	rc/rt.autolib.rc \
+	rc/libpng.rc \
+	rc/clock_gettime.func.rc \
+	rc/mach_time.h.rc \
+	rc/windows.h.rc \
+	rc/posix.rc \
+	rc/printf_lld.rc \
+	rc/extra.rc \
+	rc/all.h.precompiled.rc \
+	rc/all.hpp.precompiled.rc
+
+rc_appendln LIBS "$LIBRT"
+rc_appendln LIBS "$LIBM"
+rc_save
diff --git a/docs/cookbook/c/allconfig.do b/docs/cookbook/c/allconfig.do
new file mode 100644
index 0000000..c659d30
--- /dev/null
+++ b/docs/cookbook/c/allconfig.do
@@ -0,0 +1,27 @@
+redo-ifchange arches configure redoconf/utils.sh
+
+config() {
+	local dir="$1" arch="$2"
+	shift
+	shift
+	[ -d "$dir" ] || mkdir "$dir"
+	(
+		cd "$dir" &&
+		../configure --host="$arch" "$@" &&
+		redo-ifchange rc/CC.rc &&
+		echo "$dir"
+	) || :
+}
+
+for d in $(cat arches); do
+	if [ "$d" = "native" ]; then
+		arch=""
+	else
+		arch="$d"
+	fi
+	config "out.$d" "$arch" &
+	config "out.$d.static" "$arch" "--enable-static" &
+	config "out.$d.opt" "$arch" "--enable-optimization" &
+done
+
+wait
diff --git a/docs/cookbook/c/arches.do b/docs/cookbook/c/arches.do
new file mode 100644
index 0000000..a779ebb
--- /dev/null
+++ b/docs/cookbook/c/arches.do
@@ -0,0 +1,14 @@
+IFS=:
+echo native >$3
+if [ -z "$NO_SLOW_TESTS" ]; then
+	for dir in $PATH; do
+		for d in "$dir"/*-cc "$dir"/*-gcc; do
+			base=${d##*/}
+			arch=${base%-*}
+			if [ -x "$d" ]; then echo "$arch"; fi
+		done
+	done >>$3
+fi
+
+redo-always
+redo-stamp <$3
diff --git a/docs/cookbook/c/clean.od b/docs/cookbook/c/clean.od
new file mode 100644
index 0000000..70a02f2
--- /dev/null
+++ b/docs/cookbook/c/clean.od
@@ -0,0 +1,6 @@
+# runs from the output directory
+rm -f *~ .*~ *.rc *.log *.gch *.stamp \
+	*.[oa] *.deps \
+	*.so *.so.* *.ver \
+	*.exe *.list \
+	hello
diff --git a/docs/cookbook/c/configure b/docs/cookbook/c/configure
new file mode 100755
index 0000000..736916f
--- /dev/null
+++ b/docs/cookbook/c/configure
@@ -0,0 +1,3 @@
+#!/bin/sh
+S="$(dirname "$0")"
+. "$S/redoconf/configure.sh"
diff --git a/docs/cookbook/c/configure.help b/docs/cookbook/c/configure.help
new file mode 100644
index 0000000..ca36761
--- /dev/null
+++ b/docs/cookbook/c/configure.help
@@ -0,0 +1,17 @@
+# Automatically generated by redoconf/_all.rc.od - do not edit
+ARCH         Architecture prefix for output (eg. i686-w64-mingw32-)
+CC           C compiler name (cc)
+CPPFLAGS     Extra C preprocessor flags (eg. -I... -D...)
+CFLAGS       Extra C compiler flags (eg. -O2 -g)
+OPTFLAGS     C/C++ compiler flag overrides (eg. -g0)
+LINK         Linker name (cc)
+LDFLAGS      Extra linker options (eg. -s -static)
+LIBS         Extra libraries to always link against (eg. -lsocket)
+STATIC       Link libraries and binaries statically
+CXX          C++ compiler name (c++)
+CXXFLAGS     Extra C++ compiler flags (eg. -O2 -g)
+LIBQT4       Extra linker options for 'QtCore'
+LIBGTK2      Extra linker options for 'gtk+-2.0 gio-2.0 gdk-2.0 gdk-pixbuf-2.0'
+LIBM         Extra linker options for 'libm'
+LIBPNG       Extra linker options for 'libpng'
+PREFIX       Change installation prefix (usually /usr/local)
diff --git a/docs/cookbook/c/default.each.do b/docs/cookbook/c/default.each.do
new file mode 100644
index 0000000..0738694
--- /dev/null
+++ b/docs/cookbook/c/default.each.do
@@ -0,0 +1,10 @@
+# redo $2 in each of the registered output dirs.
+# This way you can run commands or depend on targets like:
+#    redo clean.each.do
+#    redo all.each.do
+# etc.
+redo-ifchange allconfig
+
+for dir in $(cat allconfig); do
+	echo "$dir/$2"
+done | xargs redo-ifchange
diff --git a/docs/cookbook/c/flagtest.c b/docs/cookbook/c/flagtest.c
new file mode 100644
index 0000000..34f9453
--- /dev/null
+++ b/docs/cookbook/c/flagtest.c
@@ -0,0 +1,10 @@
+#include "main.h"
+#include <stdio.h>
+
+#ifdef EXTRA_RC_INCLUDED
+#error "rc/extra.rc should not be included when compiling flagtest.c"
+#endif
+
+void flag_test(void) {
+	printf("flagtest included\n");
+}
diff --git a/docs/cookbook/c/flagtest.o.od b/docs/cookbook/c/flagtest.o.od
new file mode 100644
index 0000000..67b5c88
--- /dev/null
+++ b/docs/cookbook/c/flagtest.o.od
@@ -0,0 +1,9 @@
+# Demonstrate how to compile .o files using nonstandard
+# compiler flags.  You could also do this for a whole
+# directory using default.o.od.
+. ./redoconf.rc
+rc_include all.rc
+
+src="$S/${1%.o}.c"
+redo-ifchange "_compile" "$src"
+CC="$CC" CPPFLAGS="-DFLAGTEST_SET=42" ./_compile "$3" "$1.deps" "$src"
diff --git a/docs/cookbook/c/hello world.list.od b/docs/cookbook/c/hello world.list.od
new file mode 100644
index 0000000..d9f5200
--- /dev/null
+++ b/docs/cookbook/c/hello world.list.od	
@@ -0,0 +1,30 @@
+# This script is run from the output dir,
+# which contains a src/ symlink to the source dir.
+
+. ./redoconf.rc
+rc_include all.rc
+
+(
+	cd "$S"
+	echo "main.c"
+	echo "monotime.c"
+	echo "when.c"      # auto-generated source
+	echo "flagtest.c"  # source with different compiler flags
+
+	if [ -n "$CXX" ]; then
+		echo "slow.cc"
+	fi
+	
+	# This is unnecessarily fancy.
+	# We're just using it as an example of
+	# how to dynamically generate a .list
+	# file.
+	for d in lib*/*.list lib*/*.list.od; do
+		[ -e "$d" ] && echo "${d%%.*}.so"
+	done | uniq
+
+	printf '%s\n' "$LIBGTK2" "$LIBQT4"
+) >$3
+
+redo-always
+redo-stamp <$3
diff --git a/docs/cookbook/c/libhello/hello.c b/docs/cookbook/c/libhello/hello.c
new file mode 100644
index 0000000..5a88be9
--- /dev/null
+++ b/docs/cookbook/c/libhello/hello.c
@@ -0,0 +1,6 @@
+#include "hello.h"
+#include <stdio.h>
+
+void hello(void) {
+	printf("Hello, world!\n");
+}
\ No newline at end of file
diff --git a/docs/cookbook/c/libhello/hello.h b/docs/cookbook/c/libhello/hello.h
new file mode 100644
index 0000000..94dbff4
--- /dev/null
+++ b/docs/cookbook/c/libhello/hello.h
@@ -0,0 +1,6 @@
+#ifndef __HELLO_H
+#define __HELLO_H
+
+void hello(void);
+
+#endif /* __HELLO_H */
\ No newline at end of file
diff --git a/docs/cookbook/c/libhello/lib hello.list b/docs/cookbook/c/libhello/lib hello.list
new file mode 100644
index 0000000..9c36258
--- /dev/null
+++ b/docs/cookbook/c/libhello/lib hello.list	
@@ -0,0 +1 @@
+hello.c
diff --git a/docs/cookbook/c/libhello/lib hello.ver b/docs/cookbook/c/libhello/lib hello.ver
new file mode 100644
index 0000000..c813fe1
--- /dev/null
+++ b/docs/cookbook/c/libhello/lib hello.ver	
@@ -0,0 +1 @@
+1.2.5
diff --git a/docs/cookbook/c/main.c b/docs/cookbook/c/main.c
new file mode 100644
index 0000000..6fc2d28
--- /dev/null
+++ b/docs/cookbook/c/main.c
@@ -0,0 +1,22 @@
+#include "main.h"
+#include "libhello/hello.h"
+#include "monotime.h"
+#include "redoconf.h"
+#include <stdio.h>
+
+#if EXTRA_RC_INCLUDED != 1
+#error "EXTRA_RC was not included!"
+#endif
+
+int main() {
+	hello();
+	printf("Timestamp: %s\n", stamp_time());
+	printf("Monotime: %lld\n", monotime());
+#ifdef CXX
+	printf("Length of 'hello world': %d\n", cpp_test());
+#else
+	printf("No C++ compiler found.\n");
+#endif
+	flag_test();
+	return 0;
+}
diff --git a/docs/cookbook/c/main.h b/docs/cookbook/c/main.h
new file mode 100644
index 0000000..d2d07e4
--- /dev/null
+++ b/docs/cookbook/c/main.h
@@ -0,0 +1,19 @@
+#ifndef __MAIN_H
+#define __MAIN_H
+
+#ifdef __cplusplus
+#define CDEF extern "C"
+#else
+#define CDEF
+#endif
+
+/* when.c */
+CDEF const char *stamp_time(void);
+
+/* slow.cc */
+CDEF int cpp_test(void);
+
+/* flagtest.c */
+CDEF void flag_test(void);
+
+#endif /* __MAIN_H */
\ No newline at end of file
diff --git a/docs/cookbook/c/monotime.c b/docs/cookbook/c/monotime.c
new file mode 100644
index 0000000..784f577
--- /dev/null
+++ b/docs/cookbook/c/monotime.c
@@ -0,0 +1,58 @@
+#define __GNU_SOURCE
+/*
+ * Returns the kernel monotonic timestamp in microseconds.
+ * This function never returns the value 0; it returns 1 instead, so that
+ * 0 can be used as a magic value.
+ */
+#include "monotime.h"
+#include "redoconf.h"
+
+#if HAVE_CLOCK_GETTIME
+
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+long long monotime(void) {
+	struct timespec ts;
+	if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
+	  perror("clock_gettime");
+	  exit(98); /* really should never happen, so don't try to recover */
+	}
+	long long result = ts.tv_sec * 1000000LL + ts.tv_nsec / 1000;
+	return !result ? 1 : result;
+}
+
+#elif HAVE_MACH_TIME_H
+
+#include <mach/mach.h>
+#include <mach/mach_time.h>
+
+long long monotime(void) {
+	static mach_timebase_info_data_t timebase;
+	if (!timebase.denom) mach_timebase_info(&timebase);
+	long long result = (mach_absolute_time() * timebase.numer /
+			   timebase.denom / 1000);
+	return !result ? 1 : result;
+}
+
+#elif HAVE_WINDOWS_H
+
+#include <windows.h>
+
+/* WARNING: Not carefully tested. It might wrap around unexpectedly.
+ * Based on suggestions from:
+ * https://stackoverflow.com/questions/211257/windows-monotonic-clock
+ */
+long long monotime(void) {
+	LARGE_INTEGER tps, t;
+	QueryPerformanceFrequency(&tps); 
+	QueryPerformanceCounter(&t);
+	return t.QuadPart * 1000000LL / tps.QuadPart;
+}
+
+#else
+
+#error "No monotonic time function is available"
+
+#endif
diff --git a/docs/cookbook/c/monotime.h b/docs/cookbook/c/monotime.h
new file mode 100644
index 0000000..fca38e7
--- /dev/null
+++ b/docs/cookbook/c/monotime.h
@@ -0,0 +1,6 @@
+#ifndef __MONOTIME_H
+#define __MONOTIME_H
+
+long long monotime(void);
+
+#endif /* __MONOTIME_H */
diff --git a/docs/cookbook/c/rc/extra.rc.od b/docs/cookbook/c/rc/extra.rc.od
new file mode 100644
index 0000000..1075a71
--- /dev/null
+++ b/docs/cookbook/c/rc/extra.rc.od
@@ -0,0 +1,5 @@
+. ./redoconf.rc
+rc_include
+
+rc_appendln CPPFLAGS "-DEXTRA_RC_INCLUDED=1"
+rc_save
diff --git a/docs/cookbook/c/rc/posix.rc.od b/docs/cookbook/c/rc/posix.rc.od
new file mode 100644
index 0000000..546fc8a
--- /dev/null
+++ b/docs/cookbook/c/rc/posix.rc.od
@@ -0,0 +1,16 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+prog='
+#include <time.h>
+
+struct timespec x;
+'
+
+x=
+if ! rc_compile cc link "$prog"; then
+    x="-D_XOPEN_SOURCE=500"
+    rc_appendln CPPFLAGS "$x"
+    rc_compile cc link "$prog"
+fi
+rc_save
diff --git a/docs/cookbook/c/rc/printf_lld.rc.od b/docs/cookbook/c/rc/printf_lld.rc.od
new file mode 100644
index 0000000..dd1650e
--- /dev/null
+++ b/docs/cookbook/c/rc/printf_lld.rc.od
@@ -0,0 +1,16 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/windows.h.rc rc/Wall.rc
+
+appendln CPPFLAGS "-Werror"  # abort if any warnings
+prog='
+#include <stdio.h>
+void test() { printf("%lld", (long long)1); }
+'
+
+x=
+if ! rc_compile cc link "$prog"; then
+    x="-D__USE_MINGW_ANSI_STDIO=1"
+    rc_appendln CPPFLAGS "$x"
+    rc_compile cc link "$prog"
+fi
+rc_save
diff --git a/docs/cookbook/c/redoconf b/docs/cookbook/c/redoconf
new file mode 120000
index 0000000..f0a8b6b
--- /dev/null
+++ b/docs/cookbook/c/redoconf
@@ -0,0 +1 @@
+../../../redoconf
\ No newline at end of file
diff --git a/docs/cookbook/c/slow.cc b/docs/cookbook/c/slow.cc
new file mode 100644
index 0000000..d854f9d
--- /dev/null
+++ b/docs/cookbook/c/slow.cc
@@ -0,0 +1,10 @@
+#include <algorithm>
+#include <string>
+#include <list>
+#include <map>
+#include "main.h"
+
+int cpp_test() {
+    std::string a = "hello ", b = "world";
+    return a.length() + b.length();
+}
diff --git a/docs/cookbook/c/test.do b/docs/cookbook/c/test.do
new file mode 100644
index 0000000..54ef47b
--- /dev/null
+++ b/docs/cookbook/c/test.do
@@ -0,0 +1 @@
+redo-ifchange test.each
diff --git a/docs/cookbook/c/test.od b/docs/cookbook/c/test.od
new file mode 100644
index 0000000..f128358
--- /dev/null
+++ b/docs/cookbook/c/test.od
@@ -0,0 +1,16 @@
+exec >&2
+redo-always
+redo-ifchange all run
+if [ -x ./run ]; then
+	echo "Running: ./run ./hello\\ world"
+	./run './hello world' >"$1.out" 2>&1
+	cat "$1.out"
+	if grep -F -q 'Hello, world!' "$1.out"; then
+		echo "-- Test successful."
+	else
+		echo "-- Test failed."
+		exit 1
+	fi
+else
+	echo "Non-native platform: test skipped."
+fi
diff --git a/docs/cookbook/c/when.c.do b/docs/cookbook/c/when.c.do
new file mode 100644
index 0000000..dafe985
--- /dev/null
+++ b/docs/cookbook/c/when.c.do
@@ -0,0 +1,7 @@
+cat >$3 <<-EOF
+	const char *stamp_time(void) {
+	    return "$(date +%Y-%m-%d)";
+	}
+EOF
+redo-always
+redo-stamp <$3
diff --git a/redoconf/_all.rc.od b/redoconf/_all.rc.od
new file mode 100644
index 0000000..71a73f5
--- /dev/null
+++ b/redoconf/_all.rc.od
@@ -0,0 +1,51 @@
+. ./redoconf.rc
+
+# replace the placeholder for this function with
+# one that will save help messages for later.
+HELP="configure.help.new"
+rm -f "$HELP"
+echo '# Automatically generated by redoconf/_all.rc.od - do not edit' >"$HELP"
+helpmsg() {
+	printf '%-11s  %s\n' "$1" "$2" >>"$HELP"
+	rc_hook "$1"
+}
+
+# Remember initial set of keys provided by ./configure
+orig_keys=""
+rc_hook() {
+	contains_line "$orig_keys" "$1" || orig_keys="$orig_keys$NL$1"
+}
+
+# Include the rest of the necessary .rc files
+keys=""
+rc_hook() {
+	contains_line "$new_keys" "$1" || new_keys="$new_keys$NL$1"
+}
+allrc=
+if [ -e "$S/all.rc.od" ]; then
+	allrc=all.rc
+else
+	allrc=
+	redo-ifcreate "$S/all.rc.od"
+fi
+rc_include rc/_init.rc rc/CC.rc rc/zdefs.rc $allrc
+
+rc_helpmsg PREFIX "Change installation prefix (usually /usr/local)"
+
+IFS="$NL"
+unused=
+for d in $orig_keys; do
+	if ! contains_line "$new_keys" "$d"; then
+		unused=1
+		xecho "Error: '$d' was given to ./configure but not used." >&2
+	fi
+done
+[ -z "$unused" ] || exit 1
+
+rc_save
+
+# Now that all the rc files have run, update $S/configure.help with the
+# newly-generated help text, so it's available to new users.
+# Even if multiple output dirs are building at once, this replaces the
+# file atomically, so it should be safe.
+mv "$HELP" "$S/configure.help"
diff --git a/redoconf/_compile.od b/redoconf/_compile.od
new file mode 100644
index 0000000..4a237b9
--- /dev/null
+++ b/redoconf/_compile.od
@@ -0,0 +1,14 @@
+# See compile.od for more explanation.
+cat >$3 <<-EOF
+	#!/bin/sh -e
+	# Run the C/C++ compiler.
+	# Assumes config variables (CFLAGS, etc) are already set.
+	t="\$1" d="\$2" i="\$3"
+	IFS="$NL"
+	set -f
+	\$CC -o "\$t" -c "\$i" \\
+	  -MMD -MF "\$d" \\
+	  \$CPPFLAGS \$CFLAGS \$CXXFLAGS \$FLAGS_PCH \$xCFLAGS \$OPTFLAGS
+EOF
+chmod a+x "$3"
+redo-stamp <$3
diff --git a/redoconf/compile.od b/redoconf/compile.od
new file mode 100644
index 0000000..f379ad8
--- /dev/null
+++ b/redoconf/compile.od
@@ -0,0 +1,51 @@
+. ./redoconf.rc
+rc_include _all.rc
+redo-ifchange _compile
+
+# Subtle:
+#  - un-backslashed $ expansions ($foo, $(cmd)) are
+#    done *now*, while writing the script contents. 
+#  - backslashed $ expansions (\$foo) are written
+#    verbatim into the script, to be interpreted at
+#    the time the script is run.
+#
+# We want to insert the variable contents into the
+# script near the top, making sure they are not
+# split or interpreted at that point (hence the
+# $(shquote)).
+#
+# Further down, we want to disable wildcard expansion
+# (set -f) and split on $NL (so we change $IFS),
+# so we use backslash escapes but *not* quoting.
+
+cat >$3 <<-EOF
+	#!/bin/sh -e
+	# Run the C/++ compiler.
+	t="\$1" d="\$2" i="\$3"
+	CPPFLAGS=$(shquote "$CPPFLAGS")
+	OPTFLAGS=$(shquote "$OPTFLAGS")
+	case \$i in
+	  *.c|*.h)
+	    CC=$(shquote "$CC")
+	    CFLAGS=$(shquote "$CFLAGS")
+	    CXXFLAGS=
+	    PCH1=$(shquote "$CFLAGS_PCH")
+	    PCH2=$(shquote "$CFLAGS_PCH_FPIC")
+	    ;;
+	  *)
+	    CC=$(shquote "$CXX")
+	    [ -n "\$CC" ] || (echo "No C++ compiler available." >&2; exit 1)
+	    CFLAGS=
+	    CXXFLAGS=$(shquote "$CXXFLAGS")
+	    PCH1=$(shquote "$CXXFLAGS_PCH")
+	    PCH2=$(shquote "$CXXFLAGS_PCH_FPIC")
+	    ;;
+	esac
+	case \$PCH in
+	  1) FLAGS_PCH=\$PCH1 ;;
+	  2) FLAGS_PCH=\$PCH2 ;;
+	esac
+	. ./_compile
+EOF
+chmod a+x "$3"
+redo-stamp <$3
diff --git a/redoconf/configure.sh b/redoconf/configure.sh
new file mode 100644
index 0000000..83d77a1
--- /dev/null
+++ b/redoconf/configure.sh
@@ -0,0 +1,200 @@
+#!/bin/sh -e
+if [ -z "$S" ]; then
+	exec >&2
+	echo "configure.sh: must include this from a 'configure' script"
+	exit 99
+fi
+if [ -e "configure" ] || [ -e "rc.sh" ]; then
+	exec >&2
+	echo "$0: run this script from an empty output directory."
+	echo "  For example:"
+	echo "    (mkdir out && cd out && ../configure && redo -j10)"
+	exit 99
+fi
+
+S="$(dirname "$0")"
+rm -f src Makefile
+echo "$S" >src
+
+# Don't regenerate these files unless they're missing.  Otherwise redo
+# will treat it as a changed dependency and rebuild a bunch of files
+# unnecessarily.
+[ -e redoconf.rc ] || cat >redoconf.rc <<-EOF
+	# Automatically generated by $0
+	read -r S <src
+	. "\$S/redoconf/rc.sh"
+EOF
+
+# Instead of a symlink, we could make this a script like redoconf.rc,
+# except then we would have to redi-ifchange default.do.sh, which would
+# greatly increase the number of calls to redo-ifchange in the fast path.
+# That turns out to slow things down quite a bit.  So let redo follow
+# the symlink and note the dependency internally, which is faster.
+[ -e default.do ] || ln -sf "$S/redoconf/default.do.sh" default.do
+
+cat >Makefile <<'EOF'
+# A wrapper for people who like to type 'make' instead of 'redo'
+all $(filter-out all,$(MAKECMDGOALS)):
+	+redo "$@"
+.PHONY: $(MAKECMDGOALS) all
+EOF
+
+# Don't include rc.sh here, because that might call redo-ifchange,
+# and we're not ready for that yet.
+. "$S/redoconf/utils.sh"
+
+usage() {
+	exec >&2
+	printf 'Usage: %s %s' "$0" \
+'[options...] [KEY=value] [--with-key=value]
+
+    --prefix=       Change installation prefix (usually /usr/local)
+    --host=         Architecture prefix for output (eg. i686-w64-mingw32-)
+    --enable-static               Link libraries and binaries statically
+    --{dis,en}able-optimization   Disable/enable optimization for C/C++
+    --{dis,en}able-debug          Disable/enable debugging flags for C/C++
+    -h, --help      This help message
+'
+	if [ -e "$S/configure.help" ]; then
+		printf '\nProject-specific flags:\n'
+		sort "$S/configure.help" |
+		while read k msg; do
+			# skip blanks and comments
+			[ -n "${k%%\#*}" ] || continue
+			# skip options with syntax already explained above
+			[ "$k" != "ARCH" ] || continue
+			[ "$k" != "PREFIX" ] || continue
+			[ "$k" != "STATIC" ] || continue
+			printf '    %-15s %s\n' "$k=..." "$msg"
+		done
+	else
+		printf '\nNo extra help yet: configure.help is missing.\n'
+	fi
+	exit 1
+}
+
+upper() {
+	xecho "$1" | tr 'a-z' 'A-Z' | sed 's/[^A-Z0-9]/_/g'
+}
+
+lower() {
+	xecho "$1" | tr 'A-Z' 'a-z' | sed 's/[^a-z0-9]/-/g'
+}
+
+emit() {
+	xecho "replaceln" "$1" "$(shquote "$(rc_splitwords "$2")")"
+}
+
+emit_append() {
+	xecho "appendln" "$1" "$(shquote "$(rc_splitwords "$2")")"
+}
+
+for k in ARCH CC CXX CPPFLAGS CFLAGS CXXFLAGS \
+         OPTFLAGS LINK LDFLAGS LIBS xCFLAGS; do
+	eval v=\$$k
+	if [ -n "$v" ]; then
+		echo "$0: Fatal: '$k' environment variable is set." >&2
+		echo "  This can cause inconsistent builds." >&2
+		echo "  Pass variables as arguments to $0 instead." >&2
+		echo "  Example: $0 $k=$(shquote "$v")" >&2
+		exit 4
+	fi
+done
+
+rm -f _flags.tmp
+echo "# Auto-generated by $0" >_flags.tmp
+for d in "$@"; do
+	case $d in
+		--help|-h|-\?)
+			usage
+			;;
+		--host=*)
+			v="${d#*=}"
+			emit "ARCH" "$v"
+			;;
+		--enable-static)
+			emit "STATIC" "1"
+			;;
+		--enable-optimization)
+			emit_append OPTFLAGS "-O2"
+			;;
+		--disable-optimization)
+			emit_append OPTFLAGS "-O0"
+			;;
+		--enable-debug)
+			emit_append OPTFLAGS "-g"
+			;;
+		--disable-debug)
+			emit_append OPTFLAGS "-g0"
+			;;
+		--prefix=*)
+			v="${d#*=}"
+			emit "PREFIX" "$v"
+			;;
+		--with-[A-Za-z]*)
+			if [ "$d" = "${d%%=*}" ]; then
+				xecho "$0: in $(shquote "$d"):" \
+				      "must supply '--with-<key>=<value>'" >&2
+				exit 3
+			fi
+			k="${d%%=*}"
+			k="${k#--with-}"
+			v="${d#*=}"
+			kl=$(lower "$k")
+			if [ "$k" != "$kl" ]; then
+				xecho "$0: in $(shquote "--with-$k=..."):" \
+				      "must be all lowercase and dashes" >&2
+				exit 3
+			fi
+			ku=$(upper "$k")
+			emit "$ku" "$v"
+			;;
+		--without-[A-Za-z]*)
+			if [ "$d" != "${d%%=*}" ]; then
+				xecho "$0: in $(shquote "$d"):" \
+				      "do not supply '=...' with --without" >&2
+				exit 3
+			fi
+			k="${d#--without-}"
+			kl=$(lower "$k")
+			if [ "$k" != "$kl" ]; then
+				xecho "$0: in $(shquote "$d"):" \
+				      "must be all lowercase and dashes" >&2
+				exit 3
+			fi
+			ku=$(upper "$k")
+			# This causes tests to try to link using an extra
+			# option "NONE", which will fail, thus making the
+			# package appear missing.
+			emit "$ku" "NONE"
+			;;
+		[A-Za-z_]*=*)
+			k="${d%%=*}"
+			v="${d#*=}"
+			ku=$(upper "$k")
+			if [ "$k" != "$ku" ]; then
+				xecho "$0: in $(shquote "$d"):" \
+				      "invalid KEY=value;" \
+				      "must be all caps and underscores" >&2
+				exit 3
+			fi
+			emit "$ku" "$v"
+			;;
+		*)
+			xecho "$0: in $(shquote "$d"):" \
+			      "invalid option; use --help for help." >&2
+			exit 2
+			;;
+	esac
+done >>_flags.tmp
+
+# Avoid replacing the file if it's identical, so we don't trigger
+# unnecessary rebuilds.  redo-stamp can do this for a redo target,
+# but _flags is being generated by this configure script, which is
+# not a redo target.
+if [ -e _flags ] && cmp _flags.tmp _flags >/dev/null; then
+	rm -f _flags.tmp
+else
+	rm -f _flags
+	mv _flags.tmp _flags
+fi
diff --git a/redoconf/default.do.sh b/redoconf/default.do.sh
new file mode 100644
index 0000000..6c4de48
--- /dev/null
+++ b/redoconf/default.do.sh
@@ -0,0 +1,181 @@
+# This script starts with $PWD=output dir, $S=input dir.
+read -r S <src
+REDOCONF="$S/redoconf"
+if [ ! -d "$S" ] || [ ! -f "$REDOCONF/default.do.sh" ]; then
+	echo "default.do.sh: \$S is not set correctly." >&2
+	exit 99
+fi
+
+NL="
+"
+
+_mkdir_of() {
+	local dir="${1%/*}"
+	[ "$dir" = "$1" ] ||
+	[ -z "$dir" ] ||
+	[ -d "$dir" ] ||
+	mkdir -p "$dir"
+}
+
+# Delegate to .od files specifically for this target, if any.
+_base1=${1##*/}
+_dir1=${1%"$_base1"}
+_missing=""
+for d in "$S/$1.od" \
+         "$S/${_dir1}default.${_base1#*.}.od" \
+         "$REDOCONF/$1.od" \
+         "$REDOCONF/${_dir1}default.${_base1#*.}.od"; do
+	if [ -e "$d" ]; then
+		redo-ifchange "$d"
+		_mkdir_of "$3"
+		( PS4="$PS4[$d] "; . "$d" )
+		exit
+	else
+		missing="$missing$NL$d"
+	fi
+done
+
+_add_missing() {
+	[ -n "$missing" ] && (IFS="$NL"; set -f; redo-ifcreate $missing)
+	missing=
+}
+
+_pick_src() {
+	# Look for the source file corresponding to a given .o file.
+	# If the source file is missing, we can also build it from
+	# eg. a .c.do script.
+	#
+	# Returns the matching source file in $src, the compiler
+	# mode in $lang, and appends any redo-ifcreate targets to
+	# $missing.
+	lang=cc
+	for src in "$1.c"; do
+		[ -e "$src" ] && return
+		[ -e "$src.do" ] && return
+		missing="$missing$NL$src"
+	done
+	lang=cxx
+	for src in "$1.cc" "$1.cpp" "$1.cxx" "$1.C" "$1.c++"; do
+		[ -e "$src" ] && return
+		[ -e "$src.do" ] && return
+		missing="$missing$NL$src"
+	done
+	echo "default.do.sh: _pick_src: no source file found for '$1.*'" >&2
+	return 1
+}
+
+_objlist() {
+	local suffix="$1" list="$2" base="${2##*/}"
+	local dir="${2%"$base"}"
+	sed -Ee 's/\.(c|cc|cpp|cxx|C|c\+\+)$/'"$suffix/" <"$2" |
+	while read -r d; do
+		[ "$d" = "${d#-}" ] || continue
+		echo "$dir$d"
+	done
+}
+
+_flaglist() {
+	while read -r d; do
+		[ "$d" != "${d#-}" ] || continue
+		echo "$d"
+	done <"$1"
+}
+
+compile() {
+	redo-ifchange compile "$src" $dep
+	rm -f "$1.deps"
+	_mkdir_of "$3"
+	xCFLAGS="$xCFLAGS" PCH="$PCH" ./compile "$3" "$1.deps" "$src"
+	# TODO: make work with dependency filenames containing whitespace.
+	#   gcc writes whitespace-containing filenames with spaces
+	#   prefixed by backslash.  read (without -r) will remove the
+	#   backslashes but still use spaces for word splitting, so
+	#   it loses the distinction.  rc_splitwords() is the right
+	#   function, but currently has a max word limit.
+	read deps <"$2.deps"
+	redo-ifchange ${deps#*:}
+}
+
+case $1 in
+    *.fpic.o)
+	_pick_src "$S/${1%.fpic.o}"
+	_add_missing
+	xCFLAGS="-fPIC" PCH="2" dep="$lang-fpic.precompile" compile "$@"
+	exit  # fast path: exit as early as possible
+	;;
+    *.o)
+	_pick_src "$S/${1%.o}"
+	_add_missing
+	xCFLAGS="" PCH="1" dep="$lang.precompile" compile "$@"
+	exit  # fast path: exit as early as possible
+	;;
+    *.h.fpic.gch|*.hpp.fpic.gch)
+	src="$S/${1%.fpic.gch}"
+	xCFLAGS="-fPIC" PCH="" dep="" compile "$@"
+	# precompiled header is "unchanged" if its component
+	# headers are unchanged.
+	cat ${deps#*:} | tee $1.stamp | redo-stamp
+	;;
+    *.h.gch|*.hpp.gch)
+	src="$S/${1%.gch}"
+	xCFLAGS="" PCH="" dep="" compile "$@"
+	# precompiled header is "unchanged" if its component
+	# headers are unchanged.
+	cat ${deps#*:} | tee $1.stamp | redo-stamp
+	;;
+    *.a)
+	listf="${1%.a}.list"
+	redo-ifchange "$listf"
+	files=$(_objlist .o "$listf")
+	IFS="$NL"
+	redo-ifchange $files
+	ar q "$3" $files
+	;;
+    *.so)
+	verf="${1%.so}.ver"
+	listf="${1%.so}.list"
+	redo-ifchange link-shlib "$verf" "$listf"
+	read ver <"$verf"
+	files=$(_objlist .fpic.o "$listf")
+	xLIBS=$(_flaglist "$listf")
+	IFS="$NL"
+	redo-ifchange $files
+	xLIBS="$xLIBS" ./link-shlib "$1.$ver" $files
+	ln -s "$(basename "$1.$ver")" "$3"
+	ln -sf "$1.$ver" .
+	;;
+    *.list|*.ver)
+	if [ -e "$S/$1" ]; then
+		redo-ifchange "$S/$1"
+		_mkdir_of "$3"
+		cp "$S/$1" "$3"
+	else
+		echo "default.do.sh: no rule to build '$1'" >&2
+		exit 99
+	fi
+	;;
+    *)
+	# In unix, binary names typically don't have any special filename
+	# pattern, so we have to handle them in a catch-all here.
+	# We detect that it's intended as a binary, and not just a typo,
+	# by the existence of a .list or .list.od file with the same name,
+	# defining the list of input files.
+	#
+	# Some people like to name their binaries *.exe, eg. on Windows,
+	# even though that doesn't matter anymore, even on Windows.
+	# So use the same rules for generating a .exe as a non-.exe.
+	bin="${1%.exe}"
+	if [ -e "$S/$bin.list" -o -e "$S/$bin.list.od" ]; then
+		# a final program binary
+		redo-ifchange link "$bin.list"
+		files=$(_objlist .o "$bin.list")
+		xLIBS=$(_flaglist "$bin.list")
+		IFS="$NL"
+		redo-ifchange $files
+		xLIBS="$xLIBS" ./link "$3" $files
+	else
+		echo "default.do.sh: no rule to build '$1' or '$1.list'" >&2
+		exit 99
+	fi
+	;;
+esac
diff --git a/redoconf/default.precompile.od b/redoconf/default.precompile.od
new file mode 100644
index 0000000..b52eb24
--- /dev/null
+++ b/redoconf/default.precompile.od
@@ -0,0 +1,31 @@
+# Run the extra steps necessary before compiling
+# C/C++ programs of the specified type.
+#
+# Notably, we have to precompile any precompiled
+# headers.  We also generate redoconf.h in case
+# programs want to include it.
+. ./redoconf.rc
+rc_include _all.rc
+
+case ${1%.precompile} in
+	cc)       pch_files="$PRE_CC_TARGETS" ;;
+	cc-fpic)  pch_files="$PRE_CC_TARGETS_FPIC" ;;
+	cxx)      pch_files="$PRE_CXX_TARGETS" ;;
+	cxx-fpic) pch_files="$PRE_CXX_TARGETS_FPIC" ;;
+	*)        exit 42 ;;
+esac
+
+IFS="$NL"
+set -f
+redo-ifchange "redoconf.h" $pch_files
+
+# Subtle:
+# Don't consider this target to have changed unless
+# the precompiled header's stamp has changed.
+# We generate redoconf.h, in case
+# a C program wants to include it, but we
+# don't care if it has changed, because the C program
+# will have its own dependency on that file.
+for d in $t; do
+	cat "$d.stamp"
+done | redo-stamp
diff --git a/redoconf/link-shlib.od b/redoconf/link-shlib.od
new file mode 100644
index 0000000..e3cb976
--- /dev/null
+++ b/redoconf/link-shlib.od
@@ -0,0 +1,36 @@
+. ./redoconf.rc
+rc_include _all.rc rc/shlib.rc
+
+# Tricky quoting: see _compile.od for details.
+if [ "$HAVE_SHLIB" = 1 ]; then
+	cat >$3 <<-EOF
+		#!/bin/sh -e
+		LINK=$(shquote "$LINK")
+		LDFLAGS=$(shquote "$LDFLAGS")
+		OPTFLAGS=$(shquote "$OPTFLAGS")
+		LIBS=$(shquote "$LIBS")
+		o="\$1"
+		ob="\${o#*/}"
+		shift
+		IFS="$NL"
+		set -f
+		\$LINK -shared -o "\$o" \\
+		  -Wl,-soname,"\$ob" \\
+		  \$LDFLAGS \$OPTFLAGS \\
+		  "\$@" \\
+		  \$LIBS
+	EOF
+else
+	# If no shared library support and we try to build one,
+	# compensate by building a static library instead in the
+	# same place.
+	cat >$3 <<-EOF
+		#!/bin/sh -e
+		o="\$1"
+		shift
+		rm -f "\$o"
+		ar q "\$o" "\$@"
+	EOF
+fi
+chmod a+x "$3"
+redo-stamp <$3
diff --git a/redoconf/link.od b/redoconf/link.od
new file mode 100644
index 0000000..e416539
--- /dev/null
+++ b/redoconf/link.od
@@ -0,0 +1,22 @@
+. ./redoconf.rc
+rc_include _all.rc
+
+# Tricky quoting: see _compile.od for details.
+cat >$3 <<-EOF
+	#!/bin/sh -e
+	LINK=$(shquote "$LINK")
+	LDFLAGS=$(shquote "$LDFLAGS")
+	OPTFLAGS=$(shquote "$OPTFLAGS")
+	LIBS=$(shquote "$LIBS")
+	o="\$1"
+	shift
+	IFS="$NL"
+	set -f
+	\$LINK -o "\$o" \\
+	  -Wl,-rpath,'\$ORIGIN' \\
+	  \$LDFLAGS \$OPTFLAGS \\
+	  "\$@" \\
+	  \$LIBS
+EOF
+chmod a+x "$3"
+redo-stamp <$3
diff --git a/redoconf/rc.sh b/redoconf/rc.sh
new file mode 100644
index 0000000..a5a3cd6
--- /dev/null
+++ b/redoconf/rc.sh
@@ -0,0 +1,240 @@
+# This script starts with $PWD=output dir, $S=input dir.
+REDOCONF="$S/redoconf"
+if [ ! -d "$S" ] || [ ! -f "$REDOCONF/default.do.sh" ]; then
+	echo "default.do.sh: \$S is not set correctly." >&2
+	exit 99
+fi
+. "$REDOCONF/utils.sh"
+RC_TARGET="$1"
+rm -f "$RC_TARGET.log"
+
+redo-ifchange "$REDOCONF/rc.sh" "$REDOCONF/utils.sh"
+
+_rc_exit_check() {
+	if [ -z "$RC_INCLUDE_RAN" ]; then
+		echo "Fatal: used redoconf/rc.sh but didn't call rc_include." >&2
+		exit 99
+	elif [ -n "$RC_QUEUE" ]; then
+		echo "Fatal: must call rc_save or rc_undo before ending." >&2
+		exit 99
+	fi
+}
+trap _rc_exit_check EXIT
+
+rc_hook() {
+	# nothing by default; can be overridden
+	:
+}
+
+# Declare that a variable *named* $1 is used
+# as input for the current script, and provide
+# a help message in $2 for use with
+# configure --help-flags.
+helpmsg() {
+	# Nothing to do by default
+	rc_hook "$1"
+}
+
+# Assign the string $2 to the global variable
+# *named* by $1.
+replaceln() {
+	rc_hook "$1"
+	eval $1=\$2
+}
+
+# If $2 is nonempty, append a newline and $2 to
+# the global variable *named* by $1
+appendln() {
+	rc_hook "$1"
+	eval local tmp=\"\$$1\$NL\$2\"
+	eval $1='${tmp#$NL}'
+}
+
+# Write a command line that calls "uses $1",
+# including proper sh-escaping.
+rc_helpmsg() {
+	local cmd="helpmsg"
+	cmd="helpmsg $1 $(shquote "$2")"
+	eval "$cmd"
+	appendln RC_HELP_QUEUE "$cmd"
+}
+
+_rc_record() {
+	if ! contains_line "$RC_CHANGED" "$1"; then
+		local oldv=
+		eval oldv="\$$1"
+		eval "old$1=\$oldv"
+		RC_CHANGED="$RC_CHANGED$NL$1"
+	fi
+}
+
+# Write a command line that calls "appendln $1 $2",
+# including properly sh-escaping $2.
+rc_appendln() {
+	RC_LOG="$RC_LOG  $1 += $(shquote "$2")$NL"
+	_rc_record "$1"
+	local cmd="appendln $1 $(shquote "$2")"
+	eval "$cmd"
+	appendln RC_QUEUE "$cmd"
+}
+
+# Write a command line that replaces $1 with $2,
+# including properly sh-escaping $2.
+# This is good for variables like CC and CXX, where
+# appending isn't what we want.
+rc_replaceln() {
+	RC_LOG="$RC_LOG  $1 = $(shquote "$2")$NL"
+	_rc_record "$1"
+	local cmd="replaceln $1 $(shquote "$2")"
+	eval "$cmd"
+	appendln RC_QUEUE "$cmd"
+}
+
+# Read compiler variables from _init.rc and the listed .rc files.
+# Runs redo-ifchange to generate the .rc files as needed.
+rc_include() {
+	local d="" want="" target="$RC_TARGET" ops4="$PS4"
+	RC_INCLUDE_RAN=1
+	for d in rc/_init.rc "$@"; do
+		if [ "$d" = "${d%.rc}" ]; then
+			xecho "$0: rc_include: '$d' must end in .rc" >&2
+			exit 99
+		fi
+		if ! contains_line "$RC_INCLUDES" "$d"; then
+			want="$want$NL$d"
+			RC_INCLUDES="$RC_INCLUDES$NL$d"
+		fi
+	done
+	want="${want#$NL}"
+	if [ -n "$want" ]; then
+		xIFS="$IFS"
+		IFS="$NL"
+		set -f
+		redo-ifchange $want
+		for d in $want; do
+			IFS="$xIFS"
+			set +f
+			RC_TARGET="$d"
+			PS4="$PS4[$d] "
+			[ ! -e "$d" ] || { :; . "./$d"; }
+			PS4="$ops4"
+		done
+		IFS="$xIFS"
+		set +f
+	fi
+	unset RC_QUEUE
+	PS4="$ops4"
+	RC_TARGET="$target"
+}
+
+# Undo the currently enqueued rc_appendln and rc_replaceln
+# actions, restoring the affected variables back to their
+# original values.
+rc_undo() {
+	local xIFS="$IFS" v=
+	IFS="$NL"
+	for k in $RC_CHANGED; do
+		eval v="\$old$k"
+		eval "$k=\$v"
+	done
+	unset RC_CHANGED
+	unset RC_QUEUE
+	unset RC_LOG
+}
+
+# Write the currently active rc_include,
+# rc_replaceln, and rc_appendln commands to stdout,
+# to produce the final .rc file.
+rc_save() {
+	printf '%s' "${RC_LOG}" >&2
+	if [ -n "$RC_INCLUDES" ]; then
+		(
+			xIFS="$IFS"
+			IFS="$NL"
+			printf 'rc_include '
+			for d in $RC_INCLUDES; do
+				printf '%s ' "$d"
+			done
+			printf '\n'
+		)
+	fi
+	xecho "$RC_HELP_QUEUE"
+	xecho "$RC_QUEUE"
+	unset RC_QUEUE
+	unset RC_CHANGED
+}
+
+rc_compile() {
+	redo-ifchange "$REDOCONF/trycompile"
+	( . "$REDOCONF/trycompile" "$@" ) >>"$RC_TARGET.log" 2>&1
+}
+
+_pkg_config() {
+	(
+		IFS="$NL"
+		set -f
+		$PKG_CONFIG $PKG_CONFIG_FLAGS "$@"
+	)
+}
+
+_rc_pkg_add() {
+	local var="$1" vvar= want=
+	shift
+	if [ -n "$HAVE_PKG_CONFIG" ]; then
+		for d in "$@"; do
+			if _pkg_config --exists "$d"; then
+				want="$want $d"
+			fi
+		done
+		if [ -n "$want" ]; then
+			rc_appendln CPPFLAGS \
+				"$(rc_splitwords \
+				    "$(_pkg_config --cflags $want)")"
+			vvar="$(rc_splitwords \
+			    "$(_pkg_config --libs $want)")"
+			rc_appendln "$var" "$vvar"
+		fi
+	else
+		echo "(pkg-config is missing)" >&2
+	fi
+}
+
+# Determine whether packages listed in $2 all exists and are functional,
+# by finding them using pkg-config and running the command in $3..$n.
+#
+# If the package works:
+#   HAVE_$1 is set to 1
+#   CPPFLAGS and the variable named by $1 are updated with compiler and
+#      linker flags, respectively.
+# else:
+#   HAVE_$1 is set to blank.
+#
+# Returns success in either case.  Check detection results in the
+# HAVE_$1 variable if needed.
+rc_pkg_detect() {
+	if ! contains_line "$RC_INCLUDES" rc/pkg-config.rc; then
+		echo "Error: include pkg-config.rc before using rc_pkg_*" >&2
+		return 1
+	fi
+	if [ "$#" -lt 3 ]; then
+		echo "Error: rc_pkg_detect needs a command to test." >&2
+		return 1
+	fi
+	local var="$1" vvar="" pkgs="$2"
+	shift
+	shift
+	eval vvar="\$$var"
+	rc_helpmsg "$var" "Extra linker options for '$pkgs'"
+	if [ -z "$vvar" ]; then
+		_rc_pkg_add "$var" $pkgs
+		eval vvar="\$$var"
+	fi
+	appendln LIBS "$vvar"
+	if ("$@"); then
+		rc_replaceln "HAVE_$var" 1
+	else
+		rc_undo
+		rc_replaceln "HAVE_$var" ""
+		rc_replaceln "$var" ""
+	fi
+}
diff --git a/redoconf/rc/CC.rc.od b/redoconf/rc/CC.rc.od
new file mode 100644
index 0000000..505ee6e
--- /dev/null
+++ b/redoconf/rc/CC.rc.od
@@ -0,0 +1,68 @@
+. ./redoconf.rc
+rc_include
+
+rc_helpmsg ARCH "Architecture prefix for output (eg. i686-w64-mingw32-)"
+rc_helpmsg CC "C compiler name (cc)"
+rc_helpmsg CPPFLAGS "Extra C preprocessor flags (eg. -I... -D...)"
+rc_helpmsg CFLAGS "Extra C compiler flags (eg. -O2 -g)"
+rc_helpmsg OPTFLAGS "C/C++ compiler flag overrides (eg. -g0)"
+rc_helpmsg LINK "Linker name (cc)"
+rc_helpmsg LDFLAGS "Extra linker options (eg. -s -static)"
+rc_helpmsg LIBS "Extra libraries to always link against (eg. -lsocket)"
+rc_helpmsg STATIC "Link libraries and binaries statically"
+
+if [ -n "$CC" ]; then
+	set -- "$CC"
+else
+	if [ -n "$ARCH" ] && [ "$ARCH" = "${ARCH%-}" ]; then
+		# Make sure arch name includes trailing dash if nonempty
+		ARCH="$ARCH-"
+	fi
+	set -- \
+	    "${ARCH}cc" "${ARCH}gcc" \
+	    "${ARCH}clang" "/usr/bin/${ARCH}clang"-[0-9]* \
+	    "${ARCH}c++" "${ARCH}g++" \
+	    "${ARCH}clang++" "/usr/bin/${ARCH}clang++"-[0-9]*
+fi
+
+rc_appendln CPPFLAGS "-I."
+[ -n "$STATIC" ] && rc_appendln LDFLAGS "-static"
+
+for d in "$@"; do
+	echo "Trying C compiler: '$d'" >&2
+	if CC="$d" CXX="" LINK="$d" rc_compile cc link 'extern int i;'; then
+		rc_replaceln CC "$d"
+		rc_replaceln LINK "$d"
+
+		# mingw32 (not mingw64) generates binaries that need
+		# a dynamic libgcc at runtime for certain operations
+		# (like 64-bit integer division), which is non-obvious.
+		# Include it statically if possible, but only on Windows,
+		# which we'll detect by whether windows.h exists.
+		#
+		# If adding the option fails, maybe it's some
+		# compiler other than gcc, so that's fine.
+		x="-static-libgcc$NL-static-libstdc++"
+		appendln LDFLAGS "$x"
+		prog='#include <windows.h>'
+		if CC="$d" LINK="$d" rc_compile cc link "$prog"; then
+			rc_appendln LDFLAGS "$x"
+		fi
+
+		# Set ARCH= to the right compiler prefix, either empty
+		# (use native compiler) or something like "i686-w64-mingw32-"
+		# (terminating dash), based on the compiler name.
+		x="-${CC##*/}"
+		x="${x%-*}"
+		x="${x#-}"
+		[ -n "$x" ] && x="$x-"
+		rc_replaceln ARCH "$x"
+
+		rc_save
+		exit 0
+	fi
+done
+
+echo "Can't find a working C compiler." >&2
+rc_undo
+exit 1
diff --git a/redoconf/rc/CXX.rc.od b/redoconf/rc/CXX.rc.od
new file mode 100644
index 0000000..4859244
--- /dev/null
+++ b/redoconf/rc/CXX.rc.od
@@ -0,0 +1,35 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+rc_helpmsg CXX "C++ compiler name (c++)"
+rc_helpmsg CXXFLAGS "Extra C++ compiler flags (eg. -O2 -g)"
+
+if [ -n "$CXX" ]; then
+	set -- "$CXX"
+else
+	# Note: $ARCH has already been set correctly by CC.rc
+	set -- \
+	    "${ARCH}c++" "${ARCH}g++" \
+	    "${ARCH}clang++" "/usr/bin/${ARCH}clang++"-[0-9]*
+fi
+
+for d in "$@"; do
+	[ -n "$d" ] || continue
+	echo "Trying C++ compiler: '$d'" >&2
+	if CC="" CXX="$d" LINK="$d" rc_compile cxx link 'class A {};'; then
+		rc_replaceln CXX "$d"
+		# If the project activates CXX.rc, then we
+		# replace the C linker with C++.  This causes
+		# it to include -lstdc++, etc.
+		# A future .rc could override this again.
+		rc_replaceln LINK "$d"
+		rc_save
+		exit 0
+	fi
+done
+
+echo "Warning: Can't find a working C++ compiler." >&2
+rc_undo
+rc_replaceln CXX ""
+rc_save
+exit 0
diff --git a/redoconf/rc/Wall.rc.od b/redoconf/rc/Wall.rc.od
new file mode 100644
index 0000000..35d3b36
--- /dev/null
+++ b/redoconf/rc/Wall.rc.od
@@ -0,0 +1,9 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+rc_appendln CPPFLAGS "-Wall"
+if rc_compile cc nolink; then
+	rc_save
+else
+	rc_undo
+fi
diff --git a/redoconf/rc/Wextra.rc.od b/redoconf/rc/Wextra.rc.od
new file mode 100644
index 0000000..ec6cd3e
--- /dev/null
+++ b/redoconf/rc/Wextra.rc.od
@@ -0,0 +1,9 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+rc_appendln CPPFLAGS "-Wextra"
+if rc_compile cc nolink; then
+	rc_save
+else
+	rc_undo
+fi
diff --git a/redoconf/rc/_init.rc.od b/redoconf/rc/_init.rc.od
new file mode 100644
index 0000000..f197b14
--- /dev/null
+++ b/redoconf/rc/_init.rc.od
@@ -0,0 +1,8 @@
+if [ -e _flags ]; then
+	redo-ifchange _flags
+	cat _flags >$3
+	redo-stamp <_flags
+else
+	redo-ifcreate _flags
+	redo-stamp </dev/null
+fi
diff --git a/redoconf/rc/default.autolib.rc.od b/redoconf/rc/default.autolib.rc.od
new file mode 100644
index 0000000..53281c8
--- /dev/null
+++ b/redoconf/rc/default.autolib.rc.od
@@ -0,0 +1,18 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+base="${1#*/}"
+lib="${base%.autolib.rc}"
+LIB=$(echo "$lib" | tr 'a-z.' 'A-Z_')
+
+x="-l$lib"
+rc_appendln "LIB$LIB" "$x"
+appendln LIBS "$x"
+if rc_compile cc link ""; then
+	rc_replaceln "HAVE_$LIB" 1
+else
+	rc_undo
+	rc_replaceln "HAVE_$LIB" ""
+	rc_replaceln "LIB$LIB" ""
+fi
+rc_save
diff --git a/redoconf/rc/default.func.rc.od b/redoconf/rc/default.func.rc.od
new file mode 100644
index 0000000..2fcf87a
--- /dev/null
+++ b/redoconf/rc/default.func.rc.od
@@ -0,0 +1,13 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+base="${1#*/}"
+f="${base%.func.rc}"
+F=$(echo "$f" | tr 'a-z.' 'A-Z_')
+
+if rc_compile cc link "void $f(); void test() { $f(); }"; then
+	rc_replaceln "HAVE_$F" 1
+else
+	rc_replaceln "HAVE_$F" ""
+fi
+rc_save
diff --git a/redoconf/rc/default.h.precompiled.rc.od b/redoconf/rc/default.h.precompiled.rc.od
new file mode 100644
index 0000000..0402169
--- /dev/null
+++ b/redoconf/rc/default.h.precompiled.rc.od
@@ -0,0 +1,23 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+base="${1#rc/}"
+src="${base%.h.precompiled.rc}"
+
+# The existence of the specific gcc warning about
+# precompiled headers is a pretty good indicator
+# that they are supported in the way we expect.
+rc_appendln CFLAGS "-Winvalid-pch"
+if rc_compile cc nolink; then
+    rc_appendln CFLAGS "$x"
+
+    rc_appendln CFLAGS_PCH "-include$NL$src.h"
+    rc_appendln CFLAGS_PCH_FPIC "-include$NL$src.h.fpic"
+
+    rc_appendln PRE_CC_TARGETS "$src.h.gch"
+    rc_appendln PRE_CC_TARGETS_FPIC "$src.h.fpic.gch"
+    rc_save
+else
+    echo "Precompiled C headers not supported." >&2
+    rc_undo
+fi
diff --git a/redoconf/rc/default.h.rc.od b/redoconf/rc/default.h.rc.od
new file mode 100644
index 0000000..0057d77
--- /dev/null
+++ b/redoconf/rc/default.h.rc.od
@@ -0,0 +1,13 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+base="${1#*/}"
+h="${base%.rc}"
+H=$(echo "$h" | tr 'a-z.' 'A-Z_')
+
+if rc_compile cc nolink "#include <$h>"; then
+	rc_replaceln "HAVE_$H" 1
+else
+	rc_replaceln "HAVE_$H" ""
+fi
+rc_save
diff --git a/redoconf/rc/default.hpp.precompiled.rc.od b/redoconf/rc/default.hpp.precompiled.rc.od
new file mode 100644
index 0000000..41fc712
--- /dev/null
+++ b/redoconf/rc/default.hpp.precompiled.rc.od
@@ -0,0 +1,23 @@
+. ./redoconf.rc
+rc_include rc/CXX.rc
+
+base="${1#rc/}"
+src="${base%.hpp.precompiled.rc}"
+
+# The existence of the specific gcc warning about
+# precompiled headers is a pretty good indicator
+# that they are supported in the way we expect.
+appendln CXXFLAGS "-Winvalid-pch"
+if rc_compile cxx nolink; then
+    rc_appendln CXXFLAGS "$x"
+
+    rc_appendln CXXFLAGS_PCH "-include$NL$src.hpp"
+    rc_appendln CXXFLAGS_PCH_FPIC "-include$NL$src.hpp.fpic"
+
+    rc_appendln PRE_CXX_TARGETS "$src.hpp.gch"
+    rc_appendln PRE_CXX_TARGETS_FPIC "$src.hpp.fpic.gch"
+    rc_save
+else
+    echo "Precompiled C++ headers not supported." >&2
+    rc_undo
+fi
diff --git a/redoconf/rc/libgl.rc.od b/redoconf/rc/libgl.rc.od
new file mode 100644
index 0000000..5a98829
--- /dev/null
+++ b/redoconf/rc/libgl.rc.od
@@ -0,0 +1,12 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/pkg-config.rc
+
+prog='
+#include <GL/gl.h>
+int x = GL_VERSION_1_1;
+void f() { glPopMatrix(); }
+'
+
+rc_pkg_detect LIBGL "gl" \
+	rc_compile cc link "$prog"
+rc_save
diff --git a/redoconf/rc/libgtk2.rc.od b/redoconf/rc/libgtk2.rc.od
new file mode 100644
index 0000000..f8f55e1
--- /dev/null
+++ b/redoconf/rc/libgtk2.rc.od
@@ -0,0 +1,12 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/pkg-config.rc
+
+prog='
+#include <gtk/gtk.h>
+int x = GTK_MAJOR_VERSION;
+void f() { gtk_widget_child_focus(0, 0); }
+'
+
+rc_pkg_detect LIBGTK2 "gtk+-2.0 gio-2.0 gdk-2.0 gdk-pixbuf-2.0" \
+	rc_compile cc link "$prog"
+rc_save
diff --git a/redoconf/rc/libm.rc.od b/redoconf/rc/libm.rc.od
new file mode 100644
index 0000000..87cc3ed
--- /dev/null
+++ b/redoconf/rc/libm.rc.od
@@ -0,0 +1,25 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/pkg-config.rc
+
+prog='
+#include <math.h>
+int x = FP_NORMAL;
+volatile float y;
+void f() { y = sin(y); }
+'
+
+rc_pkg_detect LIBM libm \
+	rc_compile cc link "$prog"
+if [ -z "$HAVE_LIBM" ]; then
+	rc_undo
+	rc_replaceln HAVE_LIBM 1
+	rc_appendln LIBM "-lm"
+	appendln LIBS "$LIBM"
+	if ! rc_compile cc link "$prog"; then
+		rc_undo
+		rc_replaceln HAVE_LIBM ""
+		rc_replaceln LIBM ""
+	fi
+fi
+	
+rc_save
diff --git a/redoconf/rc/libpng.rc.od b/redoconf/rc/libpng.rc.od
new file mode 100644
index 0000000..43a11c6
--- /dev/null
+++ b/redoconf/rc/libpng.rc.od
@@ -0,0 +1,12 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/pkg-config.rc
+
+prog='
+#include <png.h>
+const char *x = PNG_LIBPNG_VER_STRING;
+void f() { png_access_version_number(); }
+'
+
+rc_pkg_detect LIBPNG libpng \
+	rc_compile cc link "$prog"
+rc_save
diff --git a/redoconf/rc/libqt4.rc.od b/redoconf/rc/libqt4.rc.od
new file mode 100644
index 0000000..e7a02eb
--- /dev/null
+++ b/redoconf/rc/libqt4.rc.od
@@ -0,0 +1,10 @@
+. ./redoconf.rc
+rc_include rc/CXX.rc rc/pkg-config.rc
+
+prog='
+#include <QVector>
+'
+
+rc_pkg_detect LIBQT4 QtCore \
+	rc_compile cxx link "$prog"
+rc_save
diff --git a/redoconf/rc/libsdl.rc.od b/redoconf/rc/libsdl.rc.od
new file mode 100644
index 0000000..1494d07
--- /dev/null
+++ b/redoconf/rc/libsdl.rc.od
@@ -0,0 +1,12 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/pkg-config.rc
+
+prog='
+#include <SDL.h>
+int x = SDL_INIT_TIMER;
+void f() { SDL_Init(0); }
+'
+
+rc_pkg_detect LIBSDL "sdl" \
+	rc_compile cc link "$prog"
+rc_save
diff --git a/redoconf/rc/libx11.rc.od b/redoconf/rc/libx11.rc.od
new file mode 100644
index 0000000..7450467
--- /dev/null
+++ b/redoconf/rc/libx11.rc.od
@@ -0,0 +1,12 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/pkg-config.rc
+
+prog='
+#include <X11/Xutil.h>
+int x = XYBitmap;
+void f() { XCreateRegion(); }
+'
+
+rc_pkg_detect LIBX11 "x11" \
+	rc_compile cc link "$prog"
+rc_save
diff --git a/redoconf/rc/pkg-config.rc.od b/redoconf/rc/pkg-config.rc.od
new file mode 100644
index 0000000..6c3f0cc
--- /dev/null
+++ b/redoconf/rc/pkg-config.rc.od
@@ -0,0 +1,17 @@
+. ./redoconf.rc
+rc_include
+
+for d in "$PKG_CONFIG" pkg-config; do
+	rc_undo
+	if "$d" --version >/dev/null 2>&1; then
+		rc_replaceln PKG_CONFIG "$d"
+		rc_replaceln HAVE_PKG_CONFIG 1
+		rc_save
+		exit 0
+	fi
+done
+
+# Failed
+rc_replaceln HAVE_PKG_CONFIG ""
+rc_replaceln PKG_CONFIG ""
+rc_save
diff --git a/redoconf/rc/run.rc.od b/redoconf/rc/run.rc.od
new file mode 100644
index 0000000..6f3f82f
--- /dev/null
+++ b/redoconf/rc/run.rc.od
@@ -0,0 +1,27 @@
+. ./redoconf.rc
+rc_include rc/CC.rc rc/windows.h.rc
+
+consider() {
+	echo "Considering RUN=$(shquote "$1")" >&2
+	if [ -z "$1" ] || type "$1" >/dev/null 2>&1; then
+		rc_undo
+		rc_replaceln RUN "$1"
+		if RUN="$RUN" rc_compile cc run ""; then
+			rc_replaceln CAN_RUN 1
+			rc_save
+			exit 0
+		fi
+	fi
+}
+
+consider ""
+if [ -n "$HAVE_WINDOWS_H" ]; then
+	consider "wine64"
+	consider "wine"
+	consider "wine32"
+fi
+
+rc_undo
+rc_replaceln RUN ""
+rc_replaceln CAN_RUN ""
+rc_save
diff --git a/redoconf/rc/shlib.rc.od b/redoconf/rc/shlib.rc.od
new file mode 100644
index 0000000..35c938f
--- /dev/null
+++ b/redoconf/rc/shlib.rc.od
@@ -0,0 +1,21 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+appendln CFLAGS "-fPIC"
+appendln LDFLAGS "-shared"
+
+prog='
+#include <stdlib.h>
+void f() { atoi(""); }
+'
+
+if [ -n "$STATIC" ]; then
+	echo "--enable-static specified; not building shared libraries." >&2
+	rc_replaceln HAVE_SHLIB ""
+elif RCC_NO_MAIN=1 rc_compile cc link "$prog"; then
+	rc_replaceln HAVE_SHLIB 1
+else
+	echo "Not building shared libraries on this platform." >&2
+	rc_replaceln HAVE_SHLIB ""
+fi
+rc_save
diff --git a/redoconf/rc/zdefs.rc.od b/redoconf/rc/zdefs.rc.od
new file mode 100644
index 0000000..7684a5f
--- /dev/null
+++ b/redoconf/rc/zdefs.rc.od
@@ -0,0 +1,11 @@
+. ./redoconf.rc
+rc_include rc/CC.rc
+
+x="-Wl,-z,defs"
+rc_appendln LDFLAGS "$x"
+if rc_compile cc link; then
+	rc_save
+else
+	echo "'$x' doesn't work on this platform; skipped." >&2
+	rc_undo
+fi
diff --git a/redoconf/rc_vars.od b/redoconf/rc_vars.od
new file mode 100644
index 0000000..c6cf4b3
--- /dev/null
+++ b/redoconf/rc_vars.od
@@ -0,0 +1,25 @@
+. ./redoconf.rc
+
+# this is called by each call to replaceln() and appendln().
+RC_KEYS="RC_KEYS"
+rc_hook() {
+	contains_line "$RC_KEYS" "$1" || RC_KEYS="$RC_KEYS$NL$1"
+}
+rc_include _all.rc
+
+# Escape double-quote and backslash so they can
+# be included as a C-style double-quoted string.
+cquote() {
+	local v="$(xecho "$1" | sed -e 's,[\"\\],\\&,g' -e 's,$, \\,')"
+	printf '"%s"' "${v% \\}"
+}
+
+(
+	echo "# Automatically generated by autovars.od"
+	for k in $(echo "$RC_KEYS" | sort); do
+		[ "$k" != "RC_INCLUDES" ] || continue
+		eval v=\$$k
+		echo "$k=$(shquote "$v")"
+	done
+) >$3
+redo-stamp <$3
diff --git a/redoconf/redoconf.h.od b/redoconf/redoconf.h.od
new file mode 100644
index 0000000..197a21e
--- /dev/null
+++ b/redoconf/redoconf.h.od
@@ -0,0 +1,34 @@
+redo-ifchange rc_vars
+. ./rc_vars
+
+NL="
+"
+
+# Escape double-quote and backslash so they can
+# be included as a C-style double-quoted string.
+cquote() {
+	local v="$(printf '%s' "$1" | sed -e 's,[\"\\],\\&,g' -e 's,$, \\,')"
+	printf '"%s"' "${v% \\}"
+}
+
+is_number() {
+	expr "$1" + 1 >/dev/null 2>&1
+}
+
+(
+	echo "/* Automatically generated by redoconf.h.od */"
+	IFS="$NL"
+	for k in $RC_KEYS; do
+		[ "$k" != "RC_KEYS" ] || continue
+		[ "$k" != "RC_INCLUDES" ] || continue
+		eval v=\$$k
+		if [ -z "$v" ]; then
+			echo "#undef $k"
+		elif is_number "$v"; then
+			echo "#define $k $v"
+		else
+			echo "#define $k $(cquote "$v")"
+		fi
+	done
+) >$3
+redo-stamp <$3
diff --git a/redoconf/run.od b/redoconf/run.od
new file mode 100644
index 0000000..104b0c1
--- /dev/null
+++ b/redoconf/run.od
@@ -0,0 +1,16 @@
+. ./redoconf.rc
+rc_include rc/run.rc
+
+if [ -n "$CAN_RUN" ]; then
+	cat >$3 <<-EOF
+		#!/bin/sh -e
+		# Run the given program, possibly under an emulator.
+		[ -n "\$1" ]
+		unset DISPLAY
+		exec $RUN "\$@"
+	EOF
+	chmod a+x "$3"
+	redo-stamp <$3
+else
+	echo "Cannot run programs; not creating run script." >&2
+fi
diff --git a/redoconf/trycompile b/redoconf/trycompile
new file mode 100644
index 0000000..b36ac10
--- /dev/null
+++ b/redoconf/trycompile
@@ -0,0 +1,71 @@
+#!/bin/sh -e
+die() {
+	echo "$0: trycompile: $*" >&2
+	exit 99
+}
+
+ctype=$1
+linktype=$2
+code=$3
+case $ctype in
+	cc)
+		[ -n "$CC" ] || die 'must set $CC first.'
+		useCC="$CC"
+		useCF="$CFLAGS"
+		useExt=".c"
+		;;
+	cxx)
+		[ -n "$CXX" ] || die 'must set $CXX first.'
+		useCC="$CXX"
+		useCF="$CXXFLAGS"
+		useExt=".cc"
+		;;
+	*)
+		die "unknown compile type '$ctype'"
+		;;
+esac
+case $linktype in
+	link|run)
+		[ -n "$LINK" ] || die 'must set $LINK first.'
+		;;
+	nolink)
+		;;
+	*)
+		die "unknown link type '$linktype'"
+		;;
+esac
+base="try.$$.tmp"
+out="$base.o"
+out2="$base.exe"
+src="$base$useExt"
+rm -f "$src" "$out" "$out2"
+set -x
+: "[trycompile]" "$@"
+main=
+[ -n "$RCC_NO_MAIN" ] || main="int main() { return 0; }"
+printf '%s' "
+    $code
+
+    $main
+" >"$src"
+NL="
+"
+IFS="$NL"
+set +e
+set -f
+# We intentionally want to split the variables here,
+# splitting on $NL, so we don't quote them.
+# 'set -f' prevents interpreting wildcards, which
+# we don't want to treat as special.
+(
+	$useCC $CPPFLAGS $useCF -o "$out" -c "$src" || exit
+	if [ "$linktype" = "link" -o "$linktype" = "run" ]; then
+		$LINK $LDFLAGS -o "$out2" "$out" $LIBS || exit
+	fi
+	if [ "$linktype" = "run" ]; then
+		$RUN "./$out2" || exit
+	fi
+)
+rv=$?
+rm -f "$src" "$out" "$out2"
+exit "$rv"
diff --git a/redoconf/utils.sh b/redoconf/utils.sh
new file mode 100644
index 0000000..9dcedeb
--- /dev/null
+++ b/redoconf/utils.sh
@@ -0,0 +1,58 @@
+NL="
+"
+
+# Like 'echo', but never processes backslash escapes.
+# (Some shells' builtin echo do, and some don't, so this
+# is safer.)
+xecho() {
+	printf '%s\n' "$*"
+}
+
+# Returns true if string $1 contains the line $2.
+# Lines are delimited by $NL.
+contains_line() {
+	case "$NL$1$NL" in
+		*"$NL$2$NL"*) return 0 ;;
+		*) return 1 ;;
+	esac
+}
+
+# Split the first (up to) 20 words from $1,
+# returning a string where the words are separated
+# by $NL instead.
+#
+# To allow words including whitespace, you can backslash
+# escape the whitespace (eg. hello\ world).  Backslashes
+# will be removed from the output string.
+#
+# We can use this to read pkg-config output, among other
+# things.
+#
+# TODO: find a POSIX sh way to eliminate the word limit.
+#  I couldn't find an easy way to split on non-backslashed
+#  whitespace without a fork-exec, which is too slow.
+#  If we resorted to bashisms, we could use 'read -a',
+#  but that's not portable.
+rc_splitwords() {
+	xecho "$1" | (
+		read v0 v1 v2 v3 v4 v5 v6 v7 v8 v9 \
+		     v10 v11 v12 v13 v14 v15 v16 v17 v18 v19 \
+		     x
+		if [ -n "$x" ]; then
+			echo "rc_splitwords: too many words" >&2
+			exit 97
+		fi
+		for d in "$v0" "$v1" "$v2" "$v3" "$v4" \
+		         "$v5" "$v6" "$v7" "$v8" "$v9" \
+		         "$v10" "$v11" "$v12" "$v13" "$v14" \
+		         "$v15" "$v16" "$v17" "$v18" "$v19"; do
+			[ -z "$d" ] || xecho "$d"
+		done
+	)
+}
+
+# Escape single-quote characters so they can
+# be included as a sh-style single-quoted string.
+shquote() {
+	printf "'%s'" "$(xecho "$1" | sed -e "s,','\\\\'',g")"
+}