avutil: Add deprecation ifdefs around obsolete intfloat code

This long-deprecated code should disappear at the next version bump.
configure: Move the bz2 and zlib checks below phtreads

There are alternate implementations of those libraries that use pthreads.
configure: Reorder pthreads checks

Some pthreads symbols might be present in libc (as shown on various *BSD)
but not all of them, leading to false positives.

Check for the most common compiler flags before the plain symbol check
to avoid known pitfalls.
doxy: Define a group for libswscale documentation

Uniform the style and eliminate a warning on newer doxygen version..
Merge commit '70a7b24d56a823894440a372c46e89e212b89c35'

* commit '70a7b24d56a823894440a372c46e89e212b89c35':
  avutil: Add deprecation ifdefs around obsolete intfloat code

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '7cbe1ea9df83ec66403fbf6400353bcb2242bf06'

* commit '7cbe1ea9df83ec66403fbf6400353bcb2242bf06':
  configure: Move the bz2 and zlib checks below phtreads

Conflicts:
	configure

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'a5a3b398fd9dce38ca50b20f182b17a256d209f2'

* commit 'a5a3b398fd9dce38ca50b20f182b17a256d209f2':
  configure: Reorder pthreads checks

Conflicts:
	configure

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  doxy: Define a group for libswscale documentation

Conflicts:
	libavutil/avutil.h
	libswscale/swscale.h

See: 18d9398143ac63915e85d76447dca5c9670ed58a
Merged-by: Michael Niedermayer <michaelni@gmx.at>
lavf/movenc: improve feedback in case of unsupported codec
lavf/movenc: return meaningful error code from mov_write_header()
ffprobe: only show tags when explicitly requested
examples/resample_audio: check av_samples_get_buffer_size() return code

Fixes CID1135757.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
examples/decoding_encoding: check av_samples_get_buffer_size() return code

Fixes CID1135756.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
avcodec/vc1: fix mb_height for field pictures

Fixes ticket2531

Tables are always allocated now with sufficient space for either progressive
or interlaced content. The alternative would be to detect a change
and reallocate.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>