Define the GLib logging domain in the following libraries: conf,
daemon, event_pipe, log.

All config_get_block_*() functions should accept constant config_param
pointers.

Renamed functions, types, variables.

gcc doesn't know that g_error() never returns.  Work around the gcc
warning.

Removed GLib logging wrappers which are not used anymore.

If a log message does not include a newline character, append it.

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().

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.

Make "secure" a log level different from "default".  "secure" should be
right between "default" and "verbose".  Map "default" to Glib's
"MESSAGE" log level.

We want to remove gcc.h eventually. This takes care of all the G_GNUC_PRINTF
macros.

We want to remove gcc.h eventually. This takes care of all the
G_GNUC_NORETURN macros.

The threshold was only checked in the deprecated logging functions
(ERROR(), WARNING(), ...).  Add the check to the GLib logging handler.

When logging to a file, log_charset would be NULL and g_convert()
would abort.

When logging to the terminal, we should print messages in the system
character set.  Convert all messages in this case.

Use the bool data type for flags.

Install a default handler which writes to stdout or stderr, and
prepends a time stamp.  This looks just like the 0.13.x logger.

The logging functions from log.h are deprecated, and the code should
use GLib logging instead.  Make ERROR(), WARNING() etc. call g_logv()
internally.

Renamed the variable "logLevel" to "log_threshold".

The warning buffer is a complex piece of code for no good reason.
Remove it and find a better solution, e.g. open the log file earlier.

Prefer GLib over utils.h.

When there are standardized headers, use these instead of the bloated
os_compat.h.

As usual, include only headers which are really needed.

I'm really no fan of the warning log, it's too complex
for how little it gets used; but fixing it is another
problem.

Do explicit casts before comparing signed with unsigned.  The one in
log.c actually fixes another warning: in the expanded macro, there may
be a check "logLevel>=0", which is always true.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7230 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Although it may not happen in mpd code, it is perfectly possible for a
newly allocated file descriptor to be zero.  For theoretical
correctness, allow 0.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7194 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This will make refactoring features easier, especially now that
pthreads support and larger refactorings are on the horizon.

Hopefully, this will make porting to other platforms (even
non-UNIX-like ones for masochists) easier, too.

os_compat.h will house all the #includes for system headers
considered to be the "core" of MPD.  Headers for optional
features will be left to individual source files.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7130 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This way we'll avoid listening on fd=0 and have a better
chance of having fd=0 as /dev/null

git-svn-id: https://svn.musicpd.org/mpd/trunk@6852 09075e82-0dd4-0310-85a5-a0d7c8717e4f