Update ext/standard/string.c

Co-authored-by: Christoph M. Becker <[email protected]>

Author: mvorisek

ext/standard/string.c

@@ -5884,7 +5884,7 @@ PHP_FUNCTION(str_split)
 
 	if ((size_t)split_length >= ZSTR_LEN(str)) {
         if (0 == ZSTR_LEN(str)) {
-            array_init_size(return_value, 0);
+            RETVAL_EMPTY_ARRAY();
         } else {
             array_init_size(return_value, 1);
             add_next_index_stringl(return_value, ZSTR_VAL(str), ZSTR_LEN(str));