ffmpeg_1: update to version 1.2.3
librsvg: move cairo dependency into propagatedBuildInputs

the pkgconfig description file of librsvg states cairo as a build requirement.
and with cairo being propagated, vlc now picks up librsvg as available.
vlc: update to version 2.0.8a

this new release together with an updated ffmpeg solves segfaults
errors, i was having for some videos.