seteuid

pub fn seteuid(euid: uid_t) usize {
    // We use setresuid here instead of setreuid to ensure that the saved uid
    // is not changed. This is what musl and recent glibc versions do as well.
    //
    // The setresuid(2) man page says that if -1 is passed the corresponding
    // id will not be changed. Since uid_t is unsigned, this wraps around to the
    // max value in C.
    comptime assert(@typeInfo(uid_t) == .int and @typeInfo(uid_t).int.signedness == .unsigned);
    return setresuid(maxInt(uid_t), euid, maxInt(uid_t));
}