[ffmpeg/f24] (12 commits) ...enable optional support for many external libraries (rfbz#4109)

Summary of changes: fd2420b... test (*) ad0b99a... Fixed build failure on rawhide due to newer opencv using a (*) d59ad3d... enable jack by default (rfbz#2156) (*) 7016e63... re-enable opencl by default (rfbz#3640 was fixed) (*) ba48e67... add conditional support for QSV via libmfx (rfbz#4043) (*) 30a5b93... drop libcelt support (*) f349d0c... drop libdirac support (unsupported by FFmpeg) (*) 1c68673... make xvidcore support optional (*) 85f7946... add missing ldconfig calls for libavdevice package (*) 43281f1... move examples from main package to -devel as docs (*) 339f85b... make DV (IEEE 1394) support optional (*) 7cfce40... enable optional support for many external libraries (rfbz#4 (*) (*) This commit already existed in another branch; no separate mail sent