We want to use the new ones in our code

- Use AVIOContext instead of ByteIOContext
- Use avformat_open_input instead of av_open_input_stream
- Use avio_alloc_context instead of init_put_byte, allocate context on the heap
- Use AVIOContext.seekable

print avformat_open_input errors

avformat_open_input is the most recent and is documented as available since
libavformat 53.2.0 (other changes happened in 52.105)
avformat_open_input was introduced in 52.94 in FFmpeg

print avformat_find_stream_info errors

Palette data is now transmitted as a side data in AVPacket

Pass its error output to msg_Err with %m

They were copied verbatim to AVDictionary equivalents some time ago

They were only used to hold one opaque pointer

Looking at the current vlc_GetCPUCount() function this can be simplified.
The sysconf(4) variable _SC_NPROCESSORS_CONF is available for OS X and OpenBSD.
The change as is also adds FreeBSD and NetBSD support to vlc_GetCPUCount().
Signed-off-by: Rafaël Carré <funman@videolan.org>

vlc headers don't declare it
This should perhaps be changed but that requires special look to atmo
code since this plugins mixes cross-platform and windows code, and vlc
and undocumented standalone compilation

Signed-off-by: Rafaël Carré <funman@videolan.org>
Modified-by: Rafaël Carré <funman@videolan.org>
    ... Replace them in ASF demux as well

Signed-off-by: Rafaël Carré <funman@videolan.org>

uint8_t cannot be more than 0xff.

This was broken ever since VLC was switched to UTF-8.

On Win32, time_t can either be long or long long depending on #define's.
This caused linking failures.

Close #5935