Accepting request 955956 from home:Pharaoh_Atem:branches:multimedia:libs

- Add patch to fix error returned with bad versions of OpenH264
  + Patch: ffmpeg-openh264-averr-on-bad-version.patch
- Enable OpenH264 as an H.264 codec via dlopen using patch from Fedora
  + Patch: ffmpeg-dlopen-openh264.patch
- Add source and script for headers for dlopening OpenH264
  + Source: ffmpeg-dlopen-headers.tar.xz
  + Source: ffmpeg_get_dlopen_headers.sh

OBS-URL: https://build.opensuse.org/request/show/955956
OBS-URL: https://build.opensuse.org/package/show/multimedia:libs/ffmpeg-5?expand=0&rev=7

enable_decoders

@@ -22,6 +22,7 @@ libcelt # celt, opus
 libcodec2 # codec2
 libdav1d # av1
 libgsm # libgsm
+libopenh264 # libopenh264_dlopen
 libopenjpeg # openjpeg
 libopus # opus
 libschroedinger # schroedinger