Porting to other platforms
--------------------------

First, determine if your OS supports the full 28 functions of the
POSIX.1e draft (if so, define HAVE_LEVEL2) or only the first 11
functions (most common case, meaning only HAVE_LEVEL1).

If your OS supports only LEVEL1, modift setup.py as appropriately;
unfortunately, the functionality of the module is quite low.

If your OS supports LEVEL2, there is a function which you must define:
testing if an acl_permset_t contains a given permission. For example,
under Linux, the acl library defines:

    int acl_get_perm(acl_permset_t permset_d, acl_perm_t perm);

under FreeBSD, the library defines ``acl_get_perm_np`` with a similar
syntax. So just see how this is implemented in your platform and either
define a simple macro or a full function with the syntax:

    static int get_perm(acl_permset_t permset_d, acl_perm_t perm);

which must return 1 if the permset contains perm and 0 otherwise.