record Signalfd : TypeA file descriptor for signal handling.
This can be used for synchronous signal handling using
(blocking) `readSignalfd` directly, or for asynchronous signal handling
using `epoll`.
.fd : Signalfd -> Bits32record SSiginfo : TypeResult type when reading from a `Signalfd`.
.ptr : SSiginfo -> AnyPtrsiginfo : SSiginfo -> PrimIO Siginfo