Added NHP_ISSET() to nua_stack.h.
Added NHP_ISSET() to nua_stack.h.

darcs-hash:20051130122905-65a35-60f4c8eae1203ec8d7707657c8ca310b608dc8f8.gz

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