Function gmtime_r 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn gmtime_r(
    timer: *const time_t,
    result: *mut tm,
) -> *mut tm

See https://pubs.opengroup.org/onlinepubs/9799919799/functions/gmtime.html.

Safety

The caller is required to ensure that:

• timer is a valid pointer
• result is convertible to an Out<tm>.