Form URL/email validation fires on empty when not required

The forms_validate function fires even when a field is not marked as required and is empty. This effectively makes all fields with validation also required. Need to fix either the regex in common.inc or the wrapper function.

This should fix it in forms.module:

    if ($func = $field->validation) {
+      if ($edit[$field->name]) {
      $func = 'valid_' . $func;
      if (function_exists($func) && !$func($edit[$field->name])) {
        form_set_error($field->name, t('Invalid entry for %field', array('%field' => '<em>' . $field->title . '</em>')));
        $error = true;
      }
+      }
    }