Dynamic commands are user commands that can be added dynamically to
the hub by a plugin.
The example plugin (mod_example.c) adds a !example command that when
invoked send a message to the user who invoked it.
- Don't link with -ldl, as it is not needed in most cases
- Don't compile plugins if USE_PLUGINS=NO
- Fix warning about missing newline at end of getopt.h
- Removed the O_NOATIME open() flag from the logging plugin.
- Removed the O_LARGEFILE open() flag. _FILE_OFFSET_BITS is 64.
- Use fsync() if fdatasync() is not available for log file writing.
- Replaced some sprintf() with snprintf() due to compiler warnings (though, they were length limited otherwise).
- Replaced two occurences of strcpy() with memcpy().
* Fix crash when unloading plugins.
* Fixed plugin loader and plugin unload handler.
* Added a new example plugin: mod_logging which logs users logging in and out of the hub to stdout.
