meson: fix PKG_CONFIG_PATH
core pkg-config files are now in 'build/meson-uninstalled'.
pkg-config files from all components will be there as well once gstreamer!4 (merged) is merged. Keep gst-plugins-base specific path for now.
core pkg-config files are now in 'build/meson-uninstalled'.
pkg-config files from all components will be there as well once gstreamer!4 (merged) is merged. Keep gst-plugins-base specific path for now.