[Perl/perl5] b32a43: locale.c: Move declaration to first uses

[Karl Williamson via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: b32a43b992a3821c86771a30baa0f2715c5f6877
      
https://github.com/Perl/perl5/commit/b32a43b992a3821c86771a30baa0f2715c5f6877
  Author: Karl Williamson <k...@cpan.org>
  Date:   2023-12-31 (Sun, 31 Dec 2023)

  Changed paths:
    M locale.c

  Log Message:
  -----------
  locale.c: Move declaration to first uses

C99 allows the clearer code of declaring a variable close to its use.

This also will be helpful in a future commit.