Function Set-Signal-Handler

Part of:

package kmrcl
( set-signal-handler < sig > < handler > )

Sets the handler for a signal to a function. Where possible, returns
the old handler for the function for later restoration with remove-signal-handler

To be portable, signal handlers should use (&rest dummy) function signatures
and ignore the value. They should return T to tell some Lisp implementations (Allegro)
that the signal was successfully handled.