Fix compiler warning

Author: youkidearitai

ext/mbstring/mbstring.c

@@ -3029,7 +3029,7 @@ static zend_string* mb_trim_default_chars(zend_string *str, MB_TRIM_MODE mode, c
 	mb_convert_buf buf;
 	mb_convert_buf_init(&buf, trim_default_chars_length, MBSTRG(current_filter_illegal_substchar), MBSTRG(current_filter_illegal_mode));
 
-	enc->from_wchar(trim_default_chars, trim_default_chars_length, &buf, true);
+	enc->from_wchar((uint32_t *)trim_default_chars, trim_default_chars_length, &buf, true);
 
 	zend_string *what = mb_convert_buf_result(&buf, enc);
 	zend_string *result = trim_each_wchar(str, what, mode, enc);