Here's a change to dynamically allocate the DSD ID3 tag buffer.
Pretty much anything with cover art is going to exceed the existing,
static 4k limit...  Here's a change to dynamically allocate the buffer
and sanity check it at some upper limit.  I rather arbitrarily pulled
256k out of thin air just to keep a corrupt file from causing it to
trying to allocate a buffer larger than available memory.

setvbuf() does not seem to have an effect on Windows.

Make sure everything gets logged right away.  No delays because
stdio's buffer is not yet full.

Without MEM_COMMIT, the reserved address space is not accessible, and
MPD crashes.

The definition of the playlist_plugin struct member of the embcue
plugin was incorrect.

Works around assertion failure due to something that appears to be a
(minor) FFmpeg bug.

Fixes bogus assertion failure.

SocketMonitor::Cancel() does not actually unregister the socket; it
only disables the event.

When mounting had not yet finished, SocketMonitor::IsDefined() was
always false, due to the workaround at the beginning of the function
that calls SocketMonitor::Steal().  This commit drops the IsDefined()
check because it was never necessary and breaks reconnect.

nfs_destroy_context() will invoke all pending callbacks with
err==-EINTR.  In CancellableCallback::Callback(), this will invoke
NfsConnection::DeferClose(), which however is only designed to be
called from nfs_service().  In non-debug mode, this will leak memory
because nfs_close_async() is never called.

Workaround: before nfs_destroy_context(), invoke nfs_close_async() on
all pending file handles.

The method NfsConnection::CancellableCallback::Callback() will always
invoke NfsConnection::Close() on the file handle, even if the void
pointer is not a nfsfh.  This can happen if the Open() was not
successful, e.g. when the file does not exist.

MEM_LARGE_PAGES does not appear to work.  Instead, MEM_RESERVE appears
to be necessary.  Until I figure this out, this large pages are
disabled.

Skipping those songs silently will confuse the client, because
commands specifying the song index within a playlist
(e.g. playlistdelete) will be out of sync.

This copies spl_print()'s behavior to playlist_file_print().

Version 2.5 fixed an API oddity, however it broke API compatibility,
at least with C++.  Disable the workaround when a libavformat version
is detected that is recent enough.

The "::" to explicitly refer to the global namespace appeared like a
good idea in C++, but it breaks with C libraries that implement
standard functions using macros (e.g. musl).

There are code paths (mostly error cases) in which it is possible to
initialize an AudioOutput and then kill it without ever calling
audio_output_new().  In such a case, its destructor will attempt to
free a mixer that was never initialized, leading to an attempt to
take out a lock on a mutex that was similarly never initialized,
which hangs forever.

Fix by always initializing the mixer appropriately.