Function svn_io_dir_make_hidden 

pub unsafe extern "C" fn svn_io_dir_make_hidden(
    path: *const c_char,
    perm: apr_fileperms_t,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Same as svn_io_dir_make(), but sets the hidden attribute on the directory on systems that support it.