ftmod_libpri: First attempt at getting AOC Facility messages going (and minor cleanups)

Requires libpri-1.4.12_beta1 or newer!
Completely untested, AOC-S/D/E ChargingRequest operations are sent to NT (DTAG BRI PTMP),
but rejected with "Unrecognized Operation".

NOTE: FreeTDM core needs support for this to be useful!
      Only AOC-E events are decoded and sent to the log.

To enable:
    Set (or add) <param name="opts" value="aoc"> in your
    libpri_spans span config.

Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

libs/freetdm/src/ftmod/ftmod_libpri/ftmod_libpri.h

@@ -42,8 +42,9 @@ typedef enum {
 	FTMOD_LIBPRI_OPT_SUGGEST_CHANNEL = (1 << 0),
 	FTMOD_LIBPRI_OPT_OMIT_DISPLAY_IE = (1 << 1),
 	FTMOD_LIBPRI_OPT_OMIT_REDIRECTING_NUMBER_IE = (1 << 2),
-		
-	FTMOD_LIBPRI_OPT_MAX = (1 << 3)
+	FTMOD_LIBPRI_OPT_FACILITY_AOC = (1 << 3),
+
+	FTMOD_LIBPRI_OPT_MAX = (1 << 4)
 } ftdm_isdn_opts_t;
 
 typedef enum {