fix warnings

libc/runestrchr.c

@@ -13,7 +13,7 @@ runestrchr(Rune *s, Rune c)
 		return s-1;
 	}
 
-	while(c1 = *s++)
+	while((c1 = *s++))
 		if(c1 == c0)
 			return s-1;
 	return 0;