use zend_str_tolower instead of php_strtolower

package.xml

@@ -47,7 +47,7 @@ It can deal with rfc822 and rfc2045 (MIME) compliant messages.
  </stability>
  <license uri="https://www.php.net/license/3_01.txt" filesource="LICENSE">PHP-3.01</license>
  <notes>
--
+- PHP 8.4 compatibility
  </notes>
  <contents>
   <dir name="/">

php_mailparse_rfc822.c

@@ -428,7 +428,11 @@ PHP_MAILPARSE_API char *php_rfc822_recombine_tokens(php_rfc822_tokenized_t *toks
 	ret[len] = 0;
 
 	if (flags & PHP_RFC822_RECOMBINE_STRTOLOWER)
+#if PHP_VERSION_ID < 80400
 		php_strtolower(ret, len);
+#else
+		zend_str_tolower(ret, len);
+#endif
 
 	return ret;
 }