Shut set but unused warnings.

Shut set but unused warnings.

	These are in the code for debug/inspection purposes.

	* src/ui/lwlib/xlwgauge.c (GaugeExpose): Use SXE_SET_UNUSED.

	* src/ui/lwlib/xlwcheckbox.c (DrawCheck):Ditto.

	* src/sysdep.c (tty_init_sys_modes_on_device)
	(tty_reset_sys_modes_on_device): Ditto.

	* src/regex.c (re_match_2_internal): Ditto.

	* src/mule/file-coding.c (Fdefine_coding_system_alias): Ditto.

	* src/media/sound-oss.c (sound_oss_handle_aj_events): Ditto.

	* src/media/sound-jack.c (sound_jack_handle_aj_events)
	(sound_jack_process): Ditto.

	* src/media/sound-ao.c (sound_ao_handle_aj_events): Ditto.

	* src/media/sound-alsa.c (sound_alsa_handle_aj_events): Ditto.

	* src/media/media-sndfile.c (media_sndfile_open): Ditto.

	* src/media/media-mad.c (media_mad_read): Ditto.

	* src/media/media-internal.c (media_internal_analyse_stream): Ditto.

	* src/emacs.c (Fdump_emacs): Ditto.

	* src/bytecode.c (execute_optimized_program): Ditto.

Signed-off-by: Nelson Ferreira <nelson.ferreira@ieee.org>