[InterNetNews/inn] ea68c8: Always add compiler options (COPT) in builds

[Julien ÉLIE]

  Branch: refs/heads/main
  Home:   https://github.com/InterNetNews/inn
  Commit: ea68c8cc42d753efdcc76ea15d4054d0b8e6c57f
      https://github.com/InterNetNews/inn/commit/ea68c8cc42d753efdcc76ea15d4054d0b8e6c57f
  Author: Julien ÉLIE <Julien-Elie at users.noreply.github.com>
  Date:   2023-07-08 (Sat, 08 Jul 2023)

  Changed paths:
    M authprogs/Makefile
    M backends/Makefile
    M contrib/Makefile
    M control/Makefile
    M expire/Makefile
    M frontends/Makefile
    M history/Makefile
    M innd/Makefile
    M innfeed/Makefile
    M lib/Makefile
    M nnrpd/Makefile
    M storage/Makefile
    M tests/Makefile

  Log Message:
  -----------
  Always add compiler options (COPT) in builds

When running "make warnings" inside a subdirectory, COPT was not taken
into account.  It was only when run at top-level.