Broken signal handling in Mintlib PL46?

[Chris Ridd <chris@imc.exec.nhs.uk>]

Whilst building Lattice versions of the mintlibs, I noticed that
the code handling signals appears to be almost completely broken :-(

I'm not too familiar with the details of how the Atari gcc port works,
so forgive me if I've got anything wrong!!

It seems to me that signals will only work when the compiler used has
32 bit integers, passed arguments on the stack, and didn't create
base-relative code.

In addition, the _trampoline function looks broken as well... Perhaps
I'm missing something, but why does _trampoline take two long args?
The Psignal specs I've read (didn't check the src though) say that
the signal handling function should take one long arg only.

Anyway, I've fixed the code. But before I upload the patches, could
someone check that what I think are errors are really errors?

Chris