Merge branch 'jc/perl' into next

* jc/perl:
  cvsimport: avoid open "-|" list form for Perl 5.6
  svnimport: avoid open "-|" list form for Perl 5.6
  send-email: avoid open "-|" list form for Perl 5.6
  rerere: avoid open "-|" list form for Perl 5.6
  fmt-merge-msg: avoid open "-|" list form for Perl 5.6