$security_settings
These are used to override or specify the security settings when
security is enabled. These are the possible settings:
PHP_HANDLING - true/false. If set to true, the
$php_handling setting is not checked for security.
IF_FUNCS - This is an array of the names of permitted
PHP functions in IF statements.
INCLUDE_ANY - true/false. If set to true, any
template can be included from the file system, regardless of the
$secure_dir list.
PHP_TAGS - true/false. If set to true, {php}{/php}
tags are permitted in the templates.
MODIFIER_FUNCS - This is an array of the names of permitted
PHP functions used as variable modifiers.