[IOS] Fix popen crash during xbmc starting up, it not work ios and may crash.
Merge pull request #2455 from ulion/fix_ios_startup_crash_on_popen

[IOS] Fix popen crash during xbmc starting up, it may not work on ios
CoreAE: fix invalid logging about mixing matrix
[osx] - fix compile after reshuffle 16f276b
Remove pointless calls.
depends: avoid being osx version dependent in ignores
CoreAE: mixing unit must have same output count as mixing map
[ios] - fix compile after reshuffle 16f276b
[ios] - kill warnings
CoreAE: fix null dereference if no mixer map was created
[atv2] - fix compile after reshuffle 16f276b
CoreAE: mixerunits input is the inputunits output

Not this still doesn't resolve all issues. We are still not
setting up a correct channel map for the output
VideoRenerers: add buffering
add buffering for GLES
WinRenderer: add buffering
DXVA: activate buffering in renderer
linuxrenderer: delete all textures on reconfigure
drop frame counter in application, ask render manager instead
vaapi: adopt to buffering in renderer
add buffering - some documentation