gplugin/gplugin

Fix plugin search with GLib 2.69.

2021-07-30, Elliott Sales de Andrade
fd4bb8956d03
Fix plugin search with GLib 2.69.

Named groups in `GRegex` with GLib 2.69 appear to return empty, not `NULL` strings, so handle that when running version comparison.

This is actually what GLib documents should happen, but I guess didn't work right before.

Testing Done:
Compiled and ran tests on Fedora Rawhide with GLib 2.69.

Reviewed at https://reviews.imfreedom.org/r/856/
The following individuals have contributed to this project.
Ankit Vani <a@nevitus.org>
EionRobb <eion@robbmob.com>
Elliott Sales de Andrade <quantum.analyst@gmail.com>
Gary Kramlich <grim@reaperworld.com>
Jason Scherer <schereja@gmail.com>
John Bailey <rekkanoryo@rekkanoryo.org>
Mike Ruprecht <cmaiku@gmail.com>
Olaf Hering <olaf@aepfle.de>
Richard Laager <rlaager@pidgin.im>
Sorvival <sorvival@tutanota.com>