Function rt_sigprocmask_raw 

pub unsafe fn rt_sigprocmask_raw(
    how: i32,
    sigset_in: *const sigset_t,
    sigset_out: *mut sigset_t,
    sigset_sz: usize,
) -> Result<(), Errno>

Make the rt_sigprocmask syscall.

Safety

• sigset_in must be safe to dereference
• sigset_out must be safe to write (uninit is ok)