Function patch_seq_signal_pending 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn patch_seq_signal_pending(
    stack: Stack,
) -> Stack

Check if a signal is pending without clearing the flag

Stack effect: ( signal-num – pending? )

Returns true if the signal was received, false otherwise. Unlike signal.received?, this does NOT clear the flag.

Safety

Stack must have an Int (signal number) on top