[InterNetNews/inn] b3abd6: Use python-config to find Python link flags

[Julien ÉLIE]

  Branch: refs/heads/main
  Home:   https://github.com/InterNetNews/inn
  Commit: b3abd6bbc6049385ec6130039f802da5ba5c6503
      https://github.com/InterNetNews/inn/commit/b3abd6bbc6049385ec6130039f802da5ba5c6503
  Author: Julien ÉLIE <Julien-Elie at users.noreply.github.com>
  Date:   2024-02-11 (Sun, 11 Feb 2024)

  Changed paths:
    M m4/python.m4

  Log Message:
  -----------
  Use python-config to find Python link flags

Thanks to Matthias Klose for the bug report, and proposal of patch
using python-config.  Fall back on the previous behaviour when
python-config is not installed.

Also, remove LOCALMODLIBS as it should not actually be used and breaks
the build with recent Python versions.  Only keep BASEMODLIBS.

close #295