Revert broken part of [6f653c5a2ba30008d62ab589ff5686df8a29ef72].

This was obviously untested as it breaks external ffmpeg build and only changes this code path.
xbmc/cores/dvdplayer/DVDDemuxers/DVDDemuxers.a(DVDDemuxFFmpeg.o): In function `DllAvFormat::av_read_frame_flush(AVFormatContext*):
/home/alexis/xbmc/lib/DllAvFormat.h:121: undefined reference to
`ff_read_frame_flush'

Even if it did not break, the change is wrong anyway.
Rename our local copy of av_read_frame_flush to xbmc_read_frame_flush as suggested by elupus on PR2633.

That way it makes it clear the function is from xmbc and not ffmpeg.
correct date formats. fixes #14286
Merge pull request #2633 from aballier/mess

Revert broken part of [6f653c5a2ba30008d62ab589ff5686df8a29ef72].
[darwin] - revert the revert the revert - well fix the build for darwin broken in a7703fb74603192f087db90c60877eeed1097f66
Merge pull request #2649 from ronie/date

correct spanish date formats. fixes #14286
[WIN32] fixed: use wide string methods to create the dump file and the stacktrace.
[AE/CA] - on LPCM only set audio-midi-setup to 8 channels when needed based on the channelcount of the stream with the highest channelcount - else set it to 2 channels if stream is only 2.0. This allows amps to switch to stereo enhancing modes (e.x. DPII) when playing 2.0 over LPCM (e.x. AAC 2.0).