Update Smarty to 3.1.21

- add missing block.tphp, block.textformat.php, function.popup.php,
  function.popup_init.php
- update function in function.html_checkboxes.php,
  function.html_options.php

www/Smarty-3.1.21/plugins/shared.literal_compiler_param.php

@@ -0,0 +1,35 @@
+<?php
+/**
+ * Smarty plugin
+ *
+ * @package    Smarty
+ * @subpackage PluginsShared
+ */
+
+/**
+ * evaluate compiler parameter
+ *
+ * @param array   $params  parameter array as given to the compiler function
+ * @param integer $index   array index of the parameter to convert
+ * @param mixed   $default value to be returned if the parameter is not present
+ *
+ * @return mixed evaluated value of parameter or $default
+ * @throws SmartyException if parameter is not a literal (but an expression, variable, …)
+ * @author Rodney Rehm
+ */
+function smarty_literal_compiler_param($params, $index, $default = null)
+{
+    // not set, go default
+    if (!isset($params[$index])) {
+        return $default;
+    }
+    // test if param is a literal
+    if (!preg_match('/^([\'"]?)[a-zA-Z0-9-]+(\\1)$/', $params[$index])) {
+        throw new SmartyException('$param[' . $index . '] is not a literal and is thus not evaluatable at compile time');
+    }
+
+    $t = null;
+    eval("\$t = " . $params[$index] . ";");
+
+    return $t;
+}