avserver: Remove unused loadable module support

There is no record of this ever being used at all, anywhere,
since the feature was added in 2effd274466.

This gets rid of extra linker tricks just to support a feature
that isn't used, simplifying portability to other platforms.

Signed-off-by: Martin Storsjö <martin@martin.st>
Employ consistent LIBAV_COMPAT_ multiple inclusion guards in compat/

Also fix a comment and an #endif comment.
compat: Add missing license boilerplates
Merge commit 'd010e95f86089abe9a3d4d4a66ac8102312d28a4'

* commit 'd010e95f86089abe9a3d4d4a66ac8102312d28a4':
  avserver: Remove unused loadable module support

Conflicts:
	configure
	ffserver.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '439902e0d68a0f0d800c21b5e6b598d5fa0c51da'

* commit '439902e0d68a0f0d800c21b5e6b598d5fa0c51da':
  Employ consistent LIBAV_COMPAT_ multiple inclusion guards in compat/

Conflicts:
	compat/aix/math.h

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

* qatar/master:
  compat: Add missing license boilerplates

Conflicts:
	compat/tms470/math.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
examples: demuxing: do partial audio packet decoding

This assumes one audio packet is decoded one time. This is not true:
packets can be partially decoded. Then you have to "adjust" the packet
and pass the undecoded part of the packet to the decode function again.
examples: demuxing: simplify audio output

There is no reason why this should copy the audio data in a very
complicated way. Also, strictly write the first plane, instead of
writing the whole buffer. This is more helpful in context of the
example. This way a user can clearly confirm that it works by playing
the written data as raw audio.
examples: demuxing: print ffplay command even if sample format is planar

Adjust the code so that a working ffplay command is printed in the
planar audio case.
swscale/input: fix 16bit gbrp input

Fixes Ticket2793

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