[Perl/perl5] ea98be: locale.c: Don't compile unused function

[Karl Williamson via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: ea98beac8b0e867a26343f8d5fb1520bf0ecac4d
      
https://github.com/Perl/perl5/commit/ea98beac8b0e867a26343f8d5fb1520bf0ecac4d
  Author: Karl Williamson <k...@cpan.org>
  Date:   2024-02-15 (Thu, 15 Feb 2024)

  Changed paths:
    M embed.fnc
    M embed.h
    M proto.h

  Log Message:
  -----------
  locale.c: Don't compile unused function

Since 0b52bb633d8c55bb15f05cdb19a4b7cb071ea271, this function isn't used
unless localeconv() is available.  Don't compile it unless that is true.