Fix building of chan_sip.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@103807 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -1473,7 +1473,7 @@ static int get_refer_info(struct sip_pvt *transferer, struct sip_request *outgoi
 static int get_also_info(struct sip_pvt *p, struct sip_request *oreq);
 static int parse_ok_contact(struct sip_pvt *pvt, struct sip_request *req);
 static int set_address_from_contact(struct sip_pvt *pvt);
-static void check_via(struct sip_pvt *p, struct sip_request *req);
+static void check_via(struct sip_pvt *p, const struct sip_request *req);
 static char *get_calleridname(const char *input, char *output, size_t outputsize);
 static int get_rpid_num(const char *input, char *output, int maxlen);
 static int get_rdnis(struct sip_pvt *p, struct sip_request *oreq);
@@ -9142,7 +9142,7 @@ static int get_also_info(struct sip_pvt *p, struct sip_request *oreq)
 	return -1;
 }
 /*! \brief check Via: header for hostname, port and rport request/answer */
-static void check_via(struct sip_pvt *p, struct sip_request *req)
+static void check_via(struct sip_pvt *p, const struct sip_request *req)
 {
 	char via[512];
 	char *c, *pt;