Make used to only use the search path for nodes that were pure
sources (not targets of other sources). This has been corrected
and now gnu-autoconf generated Makefiles work in directories other
than the source one.
- Suffix transformation rescanning:
Suffix transformations (.c.o:; cc ...) were only recognized in
the past when both suffixes were members of the suffix list.
Thus a sequence like:
.z.b:
echo ${.TARGET}
.SUFFIXES: .z
would cause .z.b: to be inserted as a regular target (and the main
target in this case). Other make programs always add rules that
start with a period in the transformation list and never consider
them as targets. We cannot do that (consider .depend files) so we
resort to scanning the list of the current targets every time a
suffix gets added, and we mutate existing targets that are now
valid transformation rules into transformation rules. If the
transformed target was also the main target, we set the main target
to be the next target in the targets list.
1. ${.*} variables did not get expanded in dependencies.
2. expanded ${.*} variables in .USE dependencies can cause tree
restructuring; handle it.
3. in compat mode, expand .USE before evaluating the list of targets,
instead of doing .USE expansions on demand, because they can cause
tree restructuring.