Media fails to load libav 58 library when using modules from maven central

When running a JavaFX application using the JavaFX modules from maven central, the native libraries are packed into the jar file, and then unpacked as needed by the JavaFX runtime. This fails for libavplugin-ffmpeg-58.so.

To reproduce this, run any media program using the modules from maven central on an Ubuntu 20.04 system that has the libavformat58 / libavcodec58 packages installed. The FX media library will fail to load the libavplugin-ffmpeg-58 support library.

When support for libav 58 was added by JDK-8215894, the new libavplugin-ffmpeg-58 library was not added to the list of dependent libraries of jfxmedia in NativeMediaManager.java. See:

https://github.com/openjdk/jfx/blob/14-ga/modules/javafx.media/src/main/java/com/sun/media/jfxmediaimpl/NativeMediaManager.java#L118