The "TAG" event is emitted by the player thread when the current
song's tag has changed.  Split this event from "PLAYLIST" and make it
a separate callback, which is more efficient.

There is only one location using PIPE_EVENT_SIGNAL: to synchronize
player_command() with player_command_finished().  Use the "notify"
library instead of the event_pipe here.

The signal_check library went out of order when we started using the
GLib main loop.  Convert the SIGHUP handler to use event_pipe instead.

event_pipe_emit_fast() is aimed for use in signal handlers: it doesn't
lock the mutex, and doesn't log on error.  That makes it potentially
lossy, but for its intended use, that does not matter.

Make the event_pipe (formerly main_notify) send/receive a set of
events, with a callback for each one.

The default event PIPE_EVENT_SIGNAL does not have a callback.  It
is still there for waking up the main thread, when it is waiting for
the player thread.

Continuing the previous patch.

We are going to migrate away from the concept of notifying the main
thread.  There should be events sent to it instead.  This patch starts
a series to implement that.

These functions are not used anymore since we use the GLib main loop.

This is a rather huge patch, which unfortunately cannot be splitted.

Instead of using our custom ioops.h library, convert everything to use
the GLib main loop.

"LOG_H" is a macro which is also used by ffmpeg/log.h.  This is
ffmpeg's fault, because short macros should be reserved for
applications, but since it's always a good idea to choose prefixed
macro names, even for applications, we are going to do that in MPD.

It'll be easier to keep track of what code runs in what
task/thread this way.

Destroy the mutex when it is not used anymore.

The select() in the main event loop blocks now (saving us many
unnecessary wakeups).  This interacted badly with the threads
that were trying to wakeup the main task via
pthread_cond_signal() since the main task was not blocked
on a condition variable, but on select().

So now if we detect a need to wakeup the player, we write
to a pipe which select() is watching instead of blindly
calling pthread_cond_signal().

git-svn-id: https://svn.musicpd.org/mpd/trunk@7347 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Also, lower the impact of compiling this w/o zeroconf by
making the init/teardown functions static no-ops.

Eventually, we should separate the Bonjour and Avahi
code into separate files and have callbacks registered
for each one, avoiding the #ifdef mess we have now...

git-svn-id: https://svn.musicpd.org/mpd/trunk@7132 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@5834 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@5238 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@5227 09075e82-0dd4-0310-85a5-a0d7c8717e4f

for log messages when outputting to console.

git-svn-id: https://svn.musicpd.org/mpd/trunk@5225 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Indent the entire tree, hopefully we can keep
it indented.

git-svn-id: https://svn.musicpd.org/mpd/trunk@4410 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@4333 09075e82-0dd4-0310-85a5-a0d7c8717e4f

header, there's no need to export it.
Static it.

git-svn-id: https://svn.musicpd.org/mpd/trunk@4330 09075e82-0dd4-0310-85a5-a0d7c8717e4f

the GPL header where necessary

git-svn-id: https://svn.musicpd.org/mpd/trunk@4317 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@2500 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@1524 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@1523 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@750 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@271 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@1 09075e82-0dd4-0310-85a5-a0d7c8717e4f