[Perl/perl5] 8c417c: Per TonyC, use GCC variant of macros

[James E Keenan via perl5-changes]

  Branch: refs/heads/smoke-me/jkeenan/scope-h-build-time-warning-20210625
  Home:   https://github.com/Perl/perl5
  Commit: 8c417c6768b722f32b344fa61c0adecd243abccd
      
https://github.com/Perl/perl5/commit/8c417c6768b722f32b344fa61c0adecd243abccd
  Author: James E Keenan <jkee...@cpan.org>
  Date:   2021-06-30 (Wed, 30 Jun 2021)

  Changed paths:
    M scope.h

  Log Message:
  -----------
  Per TonyC, use GCC variant of macros