Change escape condition

Author: Girgias

ext/standard/proc_open.c

@@ -498,7 +498,7 @@ static void append_win_escaped_arg(smart_str *str, zend_string *arg)
 	size_t num_bs = 0;
 
 	smart_str_appendc(str, '"');
-	for (size_t i = 0; i <= ZSTR_LEN(arg); ++i) {
+	for (size_t i = 0; i < ZSTR_LEN(arg); ++i) {
 		char c = ZSTR_VAL(arg)[i];
 		if (c == '\\') {
 			num_bs++;