$plugins_dir
This is the directories where Smarty will look for the plugins that it
needs. Default is "plugins" under the SMARTY_DIR. If you supply a
relative path, Smarty will first look under the SMARTY_DIR, then
relative to the cwd (current working directory), then relative to each
entry in your PHP include path.
Technical Note:
For best performance, do not setup your plugins_dir to have to use the
PHP include path. Use an absolute pathname, or a path relative to
SMARTY_DIR or the cwd.
