API changes, most recent first:
+2021-04-27 - xxxxxxxxxx - lavd yyyyyyyyy - avdevice.h
+ The av_*_device_next API functions now accept and return
+ pointers to const AVInputFormat resp. AVOutputFormat.
+
2021-04-27 - xxxxxxxxxx - lavd yyyyyyyyy - avdevice.h
avdevice_list_input_sources and avdevice_list_output_sinks now accept
pointers to const AVInputFormat resp. const AVOutputFormat.