Conflicts:
	libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_support.c

         to load the module if there is any error

Conflicts:

	libs/freetdm/mod_freetdm/mod_freetdm.c

Conflicts:
	libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn.c

freetdm - ISDN:Fix for not responding to incoming RESTARTs with RESTART ACK if there is an active call on that channel at the time the RESTART was received

this is needed to differentiate route/cfwd

Make this thing readable by wasting a couple of bytes for spaces and newlines.

As an added bonus, save some stack space by making usage_string a static const.
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>