Add support for conditionally enabling ipv6

(cherry picked from commit 6b0d84fc95)

upnp/src/api/upnpapi.c

@@ -488,7 +488,7 @@ exit_function:
 	return retVal;
 }
 
-
+#ifndef UPNP_ENABLE_IPV6
 int UpnpInit2(const char *IfName, unsigned short DestPort)
 {
 	int retVal;
@@ -535,6 +535,7 @@ exit_function:
 
 	return UPNP_E_SUCCESS;
 }
+#endif
 
 
 int UpnpFinish(void)
@@ -620,7 +621,7 @@ unsigned short UpnpGetServerPort(void)
 	return LOCAL_PORT_V4;
 }
 
-
+#ifdef UPNP_ENABLE_IPV6
 unsigned short UpnpGetServerPort6(void)
 {
 	if (UpnpSdkInit != 1) {
@@ -629,6 +630,7 @@ unsigned short UpnpGetServerPort6(void)
 
 	return LOCAL_PORT_V6;
 }
+#endif
 
 
 char *UpnpGetServerIpAddress(void)