flac: fix void pointer arithmetic warning
contrib: fix FFI build

There is no point building FFI for its own sake since VLC does not use
FFI directly on any platform.
contrib: documentation update
Waveout: Fix SPDIF output

Ref #9522
DirectSound: fix SPDIF

Close #9522
mac packages: remove obsolete Delete Preferences.app

This application is incompatible with Mavericks, and it is superseded by the mechanisms provided
within the UI itself.

Also update the readme to reflect this change.
Fix make dist
Merge remote-tracking branch: upstream/master