Make max optional in clamp()

Author: kylekatarnls

ext/standard/math.c

@@ -447,13 +447,15 @@ ZEND_FRAMELESS_FUNCTION(clamp, 3)
 		RETURN_THROWS();
 	}
 
-	if (zend_compare(zmin, zmax) > 0) {
-		zend_argument_value_error(2, "must be smaller than or equal to argument #3 ($max)");
-		RETURN_THROWS();
-	}
+	if (zmax != NULL) {
+		if (zend_compare(zmin, zmax) > 0) {
+			zend_argument_value_error(2, "must be smaller than or equal to argument #3 ($max)");
+			RETURN_THROWS();
+		}
 
-	if (zend_compare(zmax, zvalue) == -1) {
-		RETURN_COPY(zmax);
+		if (zend_compare(zmax, zvalue) == -1) {
+			RETURN_COPY(zmax);
+		}
 	}
 
 	if (zend_compare(zvalue, zmin) == -1) {