Function svn_io_dir_make_sgid 

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

Same as svn_io_dir_make(), but attempts to set the sgid on the directory on systems that support it. Does not return an error if the attempt to set the sgid bit fails. On Unix filesystems, setting the sgid bit on a directory ensures that files and subdirectories created within inherit group ownership from the parent instead of from the primary gid.

@since New in 1.1.