+ Removed asserts for (l)gpl & (l)gpl3 making it easier to enable and disable all
(l)gpl & (l)gpl3 portions
+ Fix build inputs so that nonfree software isn't pulled in when building ffmpeg
+ Fix compiler on systems with clang
+ Disable libraries that fail on darwin until they can be fixed
+ Fix linux only build inputs so that they aren't pulled in on other platforms
+ Fix optional build inputs
+ Opencv causes circular dependency issues so it is disabled until it can be resolved
/cc maintainers @codyopel, @fuuzetsu.
Release notes don't indicate any new options or dependencies.
http://git.videolan.org/?p=ffmpeg.git;a=blob;f=RELEASE_NOTES;hb=release/2.6
APIchanges looks like we should be able to replace 2.5 by 2.6
without anything breaking (belongs to staging and needs some testing).
