The problem is that both POSIX and ANSI/ISO (for C) claim that
signal handlers take only one argument, an int, specifically
the signal type.

Perhaps we should have two types of signal handlers, and a flag indicating
which kind is in place, so we can offer an extension, called by whatever
means, and provide proper prototypes for signal.  (Which we are technically
required to do, I think, because an implementation is required to diagnose
an attempt to pass an incorrect argument to signal.)

-s