Function initgroups 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn initgroups(
    user: *const c_char,
    gid: gid_t,
) -> c_int

MT-Safe locale Non-POSIX, see https://www.man7.org/linux/man-pages/man3/initgroups.3.html.

Initialize the supplementary group access list.