fix the compilation warning

src/common.c

@@ -293,7 +293,7 @@ int parsehostname(char *hostname, struct clientparam *param, unsigned short port
 
 	if(!hostname || !*hostname)return 2;
 	if(*hostname == '[') se=strchr(hostname, ']');
-	if (sp = strchr(se?se:hostname, ':')) {
+	if ((sp = strchr(se?se:hostname, ':'))) {
 		if(strchr(sp+1, ':'))sp = NULL;
 		else *sp = 0;
 	}