Replaced myFgets() with fgets() + g_strchomp().

g_ascii_isspace() includes \r and \n.  This means that lines from a
text file don't have to be chopped prior to buffer2array().

Don't do two allocations for the mod_Data structure.

The log file is duped to STDOUT_FILENO and STDERR_FILENO.  No need to
keep another copy of it in out_fd all the time.  We only need it once
once in setup_log_output().

When MPD exits, it should manually free all resources in use, to allow
easy memory leak debugging.  Make the decoder thread terminate during
that.

Allow logging to syslog if log_file is configured to "syslog".

Added log_init_file() and log_init_stdout(), preparing for other
logging targets.

The logging library currently has 3 constructor functions: initLog(),
open_log_files(), setup_log_output(), called in this order.  Merged
the first two.

Declare log_threshold as GLogLevelFlags.

If the user wants the log files with a specific mode, he has to start
MPD with the correct umask.  Don't hard-code that.

This fixes a bug: when log cycling failed, MPD would not restore the
old umask.

Merged code from open_log_files() and cycle_log_files().

Removed the "error_file" option.  There is only one log file now.  If
a user wants to see only the errors, he should configure a log_level.

This patch adds RVA2 (relative volume adjustment) tag
support to mpd, as a fallback if no replaygain tags are
found. The code is almost directly from madplay (GPL).

RVA2 tags are generated for example by the "normalize" utility.

Updated by: Avuton Olrich <avuton@gmail.com>

Use GLib locking (GMutex, GCond) instead of pthread because GLib is
more portable, e.g. on mingw32.

Don't use NOTIFY_INITIALIZER to initialize audio_output_client_notify.

Build the path with g_build_filename().  Also use g_get_home_dir() and
g_file_test().

Eliminate duplicated code.  The GLib code is much more mature than
MPD's custom parser.

Prepare for the migration to the GLib option parser, which uses
gboolean for flags.

The input_stream object should only be closed by the MPD core
(i.e. decoder_thread.c / decoder_run()).  A decoder plugin which
attempts to close it will result in a segmentation fault.

When there are no archive plugins, we do not need the archive API at
all.  Drop all its overhead.

Don't split configure options and their implementation.  Check for the
backend library before the AM_CONDITIONAL, otherwise Makefile.am will
compile the plugin although the library may not be available.