t/*: rearrange tests into numbered directories.

It was getting way too ad-hoc in there.  Let's reorganize the tests so that
there's a good, obvious, suggested sequence to run them in.

t/111-compile/CC.do

@@ -0,0 +1,11 @@
+redo-ifchange config.sh
+. ./config.sh
+exec >$3
+cat <<-EOF
+	redo-ifchange \$2.c
+	gcc $CFLAGS -MD -MF \$3.deps -o \$3 -c \$2.c
+	read DEPS <\$3.deps
+	rm -f \$3.deps
+	redo-ifchange \${DEPS#*:}
+EOF
+chmod +x $3