Check for the proper return value on an error in a call to mmap().

This was reported by Andy Wang on the asterisk-dev list.  Thanks!


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.2@48943 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

@@ -1260,7 +1260,7 @@ static int try_firmware(char *s)
 		return -1;
 	}
 	fwh = mmap(NULL, stbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0); 
-	if (!fwh) {
+	if (fwh == (void *) -1) {
 		ast_log(LOG_WARNING, "mmap failed: %s\n", strerror(errno));
 		close(fd);
 		return -1;