Since AVFilterContext are freed automatically, this wrapper class
serves no purpose.  Let's remove it.

Fixes potential double-free bugs which currently did not occur because
the destructors happened to be called in the right order.

Fixes part 1 of https://github.com/MusicPlayerDaemon/MPD/issues/1235

This enables the JACK output plugin on Windows, but doesn't link
against libjack64.dll, instead loads the DLL at runtime with
LoadLibrary().  This kludge avoids the extremely fragile JACK shared
memory protocol by using the system's libjack64.dll, without requiring
the same DLL at build time.

Shorter.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Replaces the static Duplicate() method.

To make things simpler, AllocatedString is now a non-template class.

Some FFmpeg filters change the sample format, and since MPD assumes
this never happens, this results in loud noise instead of music.  This
commit finally implements the TODO comment by sending one frame of
silence to the filter and checking the output frame's format.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1009

To be reused by the FFmpeg filter plugin.

This compatibility macro has been removed from FFmpeg long ago.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/981

Reduces header dependencies.

snprintf() is available on mingw, and the libnfs kludge broke the
build with mingw, because sprintf_s() was now both an inline function
and a "dllimport" function (because the macro renamed the inline
function snprintf() to sprintf_s() in mingw's stdio.h).

GCC5 cannot build mpd.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Need to check for it in iconv.h. Otherwise meson prefixes a __builtin variant in the check.

Preparing to replace `smbclient_mutex`, for finer-grained locking.

We no longer need to call smbc_init() because we don't need the compat
layer anymore.

As a side effect, the input plugin closes the SMB/CIFS connection
after closing the file.

This solves one part of
https://github.com/MusicPlayerDaemon/MPD/issues/916