Merge branch 'ab/regen-perl-mak-with-different-perl'

Update the build dependency so that an update to /usr/bin/perl
etc. result in recomputation of perl.mak file.

* ab/regen-perl-mak-with-different-perl:
  perl: regenerate perl.mak if perl -V changes

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) $@+