[PATCH v2] perl: regenerate perl.mak if perl -V changes

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Change the perl/perl.mak build process so that the file is re-made if
the output of "perl -V" changes.

Before this change updating e.g. /usr/bin/perl to a new major version
would cause the next "make" command to fail, since perl.mak has
hardcoded paths to perl library paths retrieved from its first run.

Now the logic added in commit ee9be06770 ("perl: detect new files in
MakeMaker builds", 2012-07-27) is extended to regeneratio
perl/perl.mak if there's any change to "perl -V".

This will in some cases redundantly trigger perl/perl.mak to be
re-made, e.g. if @INC is modified in ways the build process doesn't
care about through sitecustomize.pl, but the common case is that we
just do the right thing and re-generate perl/perl.mak when needed.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---

Maybe this'll set some sort of record for a v2 submission, but anyway,
this should clearly be >> not >, we don't want to overwrite the list
of *.pm files we just added.

 Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Makefile b/Makefile
index 9f8b35ad41..485c453ca2 100644
--- a/Makefile
+++ b/Makefile
@@ -1851,6 +1851,7 @@ perl/perl.mak: perl/PM.stamp
 
 perl/PM.stamp: FORCE
 	@$(FIND) perl -type f -name '*.pm' | sort >$@+ && \
+	$(PERL_PATH) -V >>$@+ && \
 	{ cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@; } && \
 	$(RM) $@+
 
-- 
2.11.0