The filter API allows us to implement software volume as a pluggable
filter, and we will be able to integrate libraries like SoX.

This GQuark will be used for GErrors related to malformed
configuration.

This patch fixes an assertion failure:

 Assertion `order < queue->length' failed.

This happens when the state file is saved, when there is no "current"
song: current==-1, and queue_order_to_position(-1) is called.

At the moment mpd doesn't store or restore the current track to/from
its state file when the daemon is stopped/started while in 'stopped'
state.  I believe the preferred behaviour would be to store and
restore the current track even when the daemon is in stopped state
when shutting down.

I made a small patch to adapt this behaviour. If you believe this is
not the preferred behaviour, maybe this should be realized as a
configuration option. I'm not sure how to do this, but made a small
comment, where one would have to put the option.

configure.ac refuses to run with autoconf older than 2.60, don't
bother to test for those versions in autogen.sh.

Refuse to build with automake 1.9.  1.9 is quite old already, and I'm
too lazy to test with ancient versions.

Call av_metadata_get() in a loop.

Moved the check from config_get_block_param().  Detect the duplicate
parameter when it's added, not when it's queried.

Instead of returning an artificial three-state integer, return a
"success" value and put the boolean value into a "bool" pointer.
That's a little bit more overhead, but an API which looks more
natural.

Initialize the config_entries array at compile time.  This is not only
faster, but also smaller.

This function is unused.

Due to padding, this takes the same amount of memory.

The top-level "mixer_device" and "mixer_control" options have been
deprecated by MPD 0.15, and it's safe to remove them in MPD 0.16.

When decoding a local file, the decoder thread tries to run all
matching decoders, until one succeeds.  Both file_decode() and
stream_decode() can decode a stream, but MPD closes the stream before
calling file_decode().  Problem is: when this decoder fails, and the
next's stream_decode() method is invoked, the input_stream is still
closed.  This patch reopens it.

Several users had problems with binding MPD to "localhost".  The cause
was duplicate /etc/hosts entries: the resolver library returns
127.0.0.1 twice, and of course, MPD attempts to bind to "both" of
them.  This patch makes failures non-fatal, given that at least one
address was bound successfully.  This is a workaround; users should
rather fix their /etc/hosts file.

Dump each socket address before binding to it.

list_OK is returned only after command_list_ok_begin.

This warning is useless.  I assume the author added it for debugging
purposes.

When client_defer_output() aborts the connection to the client,
client_write_output() called client_write_deferred() anyway.  This
caused an assertion failure.  Fix it by checking for the "expired"
flag again after client_defer_output() returns.

I'm hunting down a bug where client->channel==NULL during I/O
operations.  These new assertions help avoid this kind of bug in the
future.

Renamed all remaining CamelCase functions.

Just a start...

Document which commands were introduced after MPD 0.13.

When the decoder is finished, break out of the player loop only after
another player.pipe check.  We did check the pipe size a few lines
above, but that check was kind of racy.

When a music_chunk only contains a tag but no PCM data, play_chunk()
returns true without freeing the chunk.  The caller now assumes that
the chunk is moved into some music_pipe and does not bother to free it
either.

To check for leaked music_chunk objects, free the music buffer on
CLOSE_AUDIO.  This invokes an assertion check which ensures that all
chunks have been returned to the buffer.

Instead of returning the local variable "ret" which is always true at
this point, hard-code the "true" return value, because that might be
more readable.