su/Makefile.am: OSX related files optionalized
su/Makefile.am: OSX related files optionalized

darcs-hash:20060927225028-1b897-d9977883f6d3ae3b2a89fc1e546cad33b4a98115.gz

unispeech/sofia-sip,jart/sofia-sip,BelledonneCommunications/sofia-sip,BelledonneCommunications/sofia-sip,jart/sofia-sip,erdincay/sofia-sip,unispeech/sofia-sip,erdincay/sofia-sip,BelledonneCommunications/sofia-sip,xhook/sofia-sip,xhook/sofia-sip,xhook/sofia-sip,BelledonneCommunications/sofia-sip,xhook/sofia-sip,xhook/sofia-sip,unispeech/sofia-sip,jart/sofia-sip,unispeech/sofia-sip,erdincay/sofia-sip,erdincay/sofia-sip