msvc build fix
msvc build fix

darcs-hash:20080525212315-16063-ad0e1bf1526a8a8fb198cec646610576aa451299.gz

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