fix build warning for GH-16228

Author: devnexen

ext/calendar/easter.c

@@ -28,7 +28,7 @@ static void _cal_easter(INTERNAL_FUNCTION_PARAMETERS, bool gm)
 	struct tm te;
 	zend_long year, golden, solar, lunar, pfm, dom, tmp, easter, result;
 	zend_long method = CAL_EASTER_DEFAULT;
-	const zend_long max_year = ZEND_LONG_MAX / 1.25;
+	const zend_long max_year = (zend_long)((double)ZEND_LONG_MAX / 1.25);
 	bool year_is_null = 1;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS(),