macosx: fixed broken appearance of the main window in case it is linked against the 10.7 SDK but run on OS X 10.6

We want to use the new names in our code

Allocate avformat context and set its I/O context before using it
This is the correct way to it (and is documented in avformat.h)

On older OpenBSD releases you especially should not have been
using /dev/random, nowdays due to changes all the device nodes
are actually all the same so either way this code can be simplified
to not special case OpenBSD in vlc_rand_init().
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

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>