Building JavaFX with gcc 10 fails with the following error at link time:

ld: error: rt/modules/javafx.media/build/native/linux/Release/obj/gstreamer-lite/gstreamer/gst/gstallocator.o: multiple definition of 'GST_CAT_CONTEXT'
ld: rt/modules/javafx.media/build/native/linux/Release/obj/gstreamer-lite/gstreamer/gst/gst.o: previous definition here
ld: error: rt/modules/javafx.media/build/native/linux/Release/obj/gstreamer-lite/gstreamer/gst/gstallocator.o: multiple definition of 'GST_CAT_LOCKING'
ld: rt/modules/javafx.media/build/native/linux/Release/obj/gstreamer-lite/gstreamer/gst/gst.o: previous definition here
...

There are, in fact, duplicate definitions of this symbol, and gcc 10 seems to care. I traced it down to the following:

modules/javafx.media/src/main/native/gstreamer/gstreamer-lite/gstreamer/gst/gstconfig.h
   162 #ifdef GSTREAMER_LITE
   163 // We using def file to limit export, so not need to export all APIs
   164 #ifndef GST_API
---> 165 #define GST_API
   166 #endif
   167 #else // GSTREAMER_LITE
   168 #ifndef GST_API
   169 #define GST_API GST_EXPORT
   170 #endif
   171 #endif // GSTREAMER_LITE

I did a local build with GST_API defined to GST_EXPORT and it caused was able to compile and link successfully, but I don't know whether that is the right fix (presumably there is some reason we aren't using "extern").