Adapt .pc files for android (IOS?) builds, to use libgstreamer_android.so instead of discrete dependencies
Please see here for context, including comments from @slomo GStreamer #2999 gtk-rs-code #1196
When building for android (IOS?) the recommended deployment is a single shared lib (typically called libgstreamer_android.so)
In the build .pc files, for android builds (IOS?), these discrete dependencies should be replaced with the mono-lib libgstreamer_android.so