gst-uninstalled: Don't add validate plugins to GST_PLUGIN_PATH Validate plugins are automatically scanned from GST_VALIDATE_PLUGIN_PATH instead. Adding them to GST_PLUGIN_PATH causes race conditions as the plugins may be loaded before validate itself.
I included this commit to make cherry-picking the more important commit easier:
gst-uninstalled: Fix compatibility with meson 0.50 Starting with Meson 0.50, meson instrospect --targets uses a list for the filename and install_filenames of each target. Handle both lists and strings.
And this simple quality-of-life commit:
gst-uninstalled.py: Look for both 'build' and '_build' for builddir
The other commits seemed too invasive to me to backport.