add new SyslogHandler class

[subsven]

Since there is currently no syslog support in Monolog (and it even was on your todo list :-) ) here is a new SyslogHandler class.

A basic usage example:

   $log = new Logger('application');
   $syslog = new SyslogHandler('myfacility', 'local6');
   $formatter = new LineFormatter("%channel%.%level_name%: %message% %extra%");
   $syslog->setFormatter($formatter);
   $log->pushHandler($syslog);

The special formatter is needed since the timestamp is included automatically in all syslog messages.
The facility can be given using PHP constants (LOG_LOCAL5) or by string ('local5') to simplify setting the values from a configuration file.

I couldn't think of any unit test approaches for actually writing the message since mocking the syslog() function isn't possible and all tests using the real syslog() function would depend on a special syslogd configuration. So currently the unit tests only cover the constructor.

[Seldaek]

Is there a good reason for adding LOG_NDELAY here? Sounds to me like you want to lazy-load that stuff in case nothing is worth logging.

[subsven]

You're probably right, using LOG_NDELAY doesn't bring any benefits. I initially suspected that I would be able to catch connection problems (missing unix domain socket of syslogd etc.) initially when setting up logging - but a look at the openlog(3) manpage reveals the profile of the real openlog() libc function:
void openlog(const char *ident, int option, int facility);
So the behaviour "Returns TRUE on success or FALSE on failure" described in the openlog() PHP documentation is nonsense - the PHP source code shows that openlog() always returns TRUE.

So - yes, you are right, LOG_NDELAY is really useless in this case. I'll update the pull request.

[Seldaek]

Thanks, I'll merge this later today then.

[Seldaek]

Merged, just had to adjust some details for coding style & windows support, thanks again