Unfortunately, there's no "optimized" implementation here.  We can't
use Linux's proprietary system call dup3(), because it would require
us to specify the new descriptor.

This also fixes installation when no *.gif files found in 'doc/api/html' folder.

This hack creates a copy of doc/doxygen.conf with the INPUT setting
replaced.

Free the temporary path string in apply_song_metadata().

Use the functions song_save() and song_load() to use the same format
as in the database file for those songs which need the tags.

While this is not useful for the database, it may become useful for
reusing this code for the state file.

Don't try db_get_song() if the URI has a scheme.

If a song with an absolute path points inside the music directory,
print only the relative part.  This happens when partial songs from a
playlist file were loaded.

I've already changed the "playlistinfo" command to hide HTTP
passwords, but forgot to do the same for the simpler "playlist"
command.  This patch changes queue_print_uris() to use the code from
song_print_uri().

The only caller doesn't use its return value, and the value isn't
useful anyway.

Don't use a large stack buffer.

Let the C compiler concatenate string constants.

MPD doesn't have child processes anymore, and thus we're not expecting
to receive SIGCHLD very often.  Since hard disk access isn't
interrupted by signals anyway, we don't need those excessive checks.

The function playlist_metadata_load() will overwrite the input buffer
before using the "name" parameter; since "name" points to the same
buffer, we'll get a corrupted string.

Don't open the music directory for each "lsinfo" call.  Get the list
of playlist files from the memory database.

.. and several accessor inline functions, to simplify the calling
code.

Conflicts:
	NEWS
	configure.ac

Some users reported that MPD crashes when using a new CURL version
with the threaded DNS resolver enabled.  It seems that
curl_multi_fdset() returns no file descriptor when the DNS resolver
runs in another thread, so MPD does not have any event to wait for.

On the CURL mailing list, somebody suggested to sleep for a fixed
amount of time.  This is not an elegant solution, because daemons
should never have to sleep without waiting for an event.  I hope the
CURL developers will review the API and remove the threaded DNS
resolver.

Meanwhile, I'm removing the assertion in question, to allow those
unfortunate users running the latest CURL version to continue using
MPD.

Use curl_multi_timeout() to determine the select() timeout, instead of
hard-coding one second.

RVA2 tags only store the "gain" value, there is no "peak" attribute.