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

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