Make AVIO_FLAG_ access constants work as flags, and in particular fix
the behavior of functions (such as avio_check()) which expect them to
be flags rather than modes.
This breaks API.
This also lists the objects from those two libraries as internal (by adding
the ff_ prefix) so that they can then be hidden via linker scripts.
(cherry picked from commit c6610a216ed2948885772154a2eed696e0cb4aca)
This is a write-only protocol which computes the md5sum of data written,
and on close writes this to the designated output or stdout if none
is specified. It can be used to test muxers without writing an actual
file.
Originally committed as revision 24309 to svn://svn.ffmpeg.org/ffmpeg/trunk