The functions were not "const" (they examined values pointed
by arguments passed to them, quoting gcc's doc: "Note that
a function that has pointer arguments and examines the data
pointed to must _not_ be declared 'const'.") but rather
"pure" and still not all of them.

Note also, that even some of the functions declared "pure"
are not pure, however, due to reasons stated in source code
the attribute has been kept.

The "group" configuration option is similar to "user" as it
sets user set what group MPD shall run as.  With "user"
option, MPD changed GID to the GID of the user, however,
more control could be desired.

Moreover, the patch changes the way of checking whether no
setuid(2)/setgid(2) is required -- previously user names
were compered, now UID and GIDs are compered (ie. the one we
already have (getuid(2)/getgid(2)) with the one we want to
change to).

The GLib functions are more portable.

Added another glue function in main().

The glue_*() functions act as a glue between MPD's main() function and
its libraries.  They handle disabled features, and pass validated
configuration options.

No CamelCase.

Since version 0.14, MPD has been logging to standard error instead of
standard output.  The option name should reflect that.  The old option
continues to work, we will remove it in a future MPD release.

Renamed type, variables and functions.

Add the "const" attribute to functions when their return value only
depends on parameters.  This allows gcc to eliminate some function
calls.

If the encoder plugin API is disabled at compile time, don't compile
test/run_encoder.c.

Parse the state file line by line, let each subsystem probe a line.
Only the playlist_state code gets the FILE pointer to read the
following lines.

Return early from the destructor function when there is no configured
state file.  Don't check the timer, don't call g_free(NULL).

Print "Loading" instead of "Saving" in state_file_read().  Added debug
message to state_file_write().

This encoder plugin is a replacement for the LAME encoder plugin for
those who prefer a "free" (non-patent encumbered) encoder library.
Most of the plugin source code is copied from the LAME encoder plugin,
since the LAME and TwoLAME APIs are nearly the same.

Fail when a feature is enabled, but the library is not found.

Don't append these to MPD_CFLAGS and MPD_LIBS.

Those were only wrappers for playlist_state_{save,restore}().  Since
sf_callbacks has been removed, we can call the latter functions
directly.

There are very few callbacks, and they are not meant to be pluggable.
Let's eliminate the array and call the load/save functions manually.

The first patch by Patrick didn't work, because his "#ifdef HAVE_OSX"
line would have required config.h.

External cue sheet file for "file.flac" should be named as "file.flac.cue".

According to the ID3 2.4 documentation, "TOPE" is "Original
artist/performer", not "performer".  Removed "TOPE" support.  Instead,
map TPE3 ("Conductor/performer refinement") and TPE4 ("Interpreted,
remixed, or otherwise modified by") to "performer".

The tag_id3.c library supports both the documented "TSO2" tag, and the
inofficial TXXX/ALBUMARTISTSORT.

The Vorbis/FLAC decoder automatically supports the new tag, without
further change.

If the encoder plugin API is disabled at compile time, don't compile
test/run_encoder.c.

The variables "success" and "error" are only used if SQLite support is
enabled.

Very few lines to log a song URI when it has been entirely played.
Then mpd logs can be parsed to do statistics.

Initialize flac_data.tag right after flac_data_init().  This way, the
"goto fail" won't jump to the point where tag_free(NULL) can be
called.

Do all the software volume stuff inside each output thread, not in the
player thread.  This allows one software mixer per output device, and
also allows the user to configure the mixer type (hardware or
software) for each audio output.

This moves the global "mixer_type" setting into the "audio_output"
section, deprecating the "mixer_enabled" flag.

The special-purpose function is used for saving/restore the software
volume control to the state file.

This mixer plugin may be used instead of the traditional global
software mixer.  It integrates with the "volume" filter plugin, and
can control the software volume of an audio output which has no
hardware mixer.