docs/cookbook/redoconf-simple: a simple redoconf C++ project.

This is a little simpler than the docs/cookbook/c project, which
doesn't actually have a doc yet because there was too much to explain.
I think I might make that a follow-on cookbook chapter, for people who
have read this simple one.

I think this doc is maybe a little too long; I intended it to be
"here's what you do to get started" but it turned into "here's what you
do to get started, and why it works, in excruciating detail." Not quite
sure how to fix.

(Also updated some other parts of the docs to refer to redoconf as a
real thing now instead of a "maybe someone should write this" thing.)

docs/cookbook/redoconf-simple/all.rc.od

@@ -0,0 +1,34 @@
+# Specify which redoconf modules to use when building
+# our program.
+#
+# The rc_include function is available in every *.od
+# script in a redoconf project.
+rc_include \
+	rc/CXX.required.rc \
+	rc/Wextra.rc \
+	rc/all.hpp.precompiled.rc \
+	rc/openssl__ssl.h.rc \
+	rc/openssl__opensslv.h.rc \
+	rc/libssl.rc \
+	rc/libm.rc
+
+# We'll link *all* our binaries with the detected
+# $LIBSSL by default. We rc_included rc/libssl.rc
+# instead of rc/libssl.required.rc, so if it's
+# not available, this line won't add any
+# libraries. It'll be up to the program to check
+# for HAVE_LIBSSL before trying to call it.
+#
+# If we wanted to only link $LIBSSL into certain
+# binaries, we would include $LIBSSL explicitly in
+# the .list.od file for those binaries.  Since we're
+# putting it here, it doesn't have to be in the .list
+# file.
+rc_appendln LIBS "$LIBSSL"
+
+# Combine all the redoconf settings we've collected
+# above, and write them to $3 (all.rc). all.rc is
+# a special .rc file that is used when generating
+# the automatic ./compile and ./link scripts, among
+# others.
+rc_save