Declare and initialize MPD_LIBS and MPD_CFLAGS before the "OS specific
defaults" section.

Both are unused.

Yesterday's patch set changed tagItemFoundAndMatches() and moved the
strcmp() return value into a bool, but forgot to add the ==0 check.

"#ifdef G_BYTE_ORDER == G_BIG_ENDIAN" cannot work, of course.

Zeroconf, curl, libsamplerate.  No libid3tag for now, because
libid3tag should be automatically disabled when no decoders using it
are enabled.

Don't separate basic options from their according tests.  Due to lots
of interdependencies, we won't do that for the plugins yet.

Print input plugins first, then archive, metadatab, decoder,
converter, encoder, output plugins.

Initialize the CFLAGS (warnings, errors) after all the libraries,
because some library checks may be broken with -Werror or -pedantic.

AC_CHECK_HEADERS defines HAVE_LOCALE_H, so we don't have to manually
define HAVE_LOCALE.

First do the checks for mandatory stuff (libc features, glib,
pkg-config), then all the options.

Don't check for inttypes.h and langinfo.h.

Fix a typo.

Use g_strndup() instead of g_memdup().

Make db_load(), db_save() and db_check() return bool instead of int.

For updating the database, directory_update_init() should be called
explicitly.

It's unused.

The notify library is easier to use, and has no disadvantages.

Start the daemon after --create-db.  This makes --create-db a flag
which discards the old database and starts with a fresh one.

Handle the DELETE and UPDATE events in separate callbacks:
song_delete_event() safely deletes a song, and update_finished_event()
is called when database update is complete.

GLib mandates that you initialize all GError objects with NULL prior
to passing it.

Pass NULL instead of &error to g_convert().  We're not interested in
the error object.

Use GLib's g_build_filename() instead of pfx_dir().

directory_is_root() is cheaper than
isRootDirectory(directory_get_path()).

Don't call command_error() if loading a song from the playlist fails.
This may result in assertion failures, since command_error() may be
called more than once.

The struct delete_data has only one member left and can be eliminated.

Determine the suffix manually, and use decoder_plugin_from_suffix()
and archive_plugin_from_suffix() instead.

This way, song_file_update_inarchive() can be optimized: it does not
have to translate its path.

Newline characters are already checked in skip_path() (update.c).

Don't include headers which are not used.  Fix some includes in
decoder_thread.c.

Reverse the condition: delete directories which don't exist anymore.
This typo caused a slowdown during partial database update.

For internal checks (i.e. not in command.c), we need to check whether
an URI is in the databse, in the local file system or a remote URI
with a scheme.