WIN-08: win32 patch to prims.cc

[Andrew Haley]

Adam Megacz writes:
 > 
 > Andrew Haley <aph@cambridge.redhat.com> writes:
 > > Can you put the exception handler code in a separate header file?
 > 
 > Sorry, I didn't notice this message until after I had committed.
 > 
 > Yes, I can move it to another file -- how about win32-threads.cc? If
 > there were a win32-signals.cc, that would make more sense, but I don't
 > think it makes sense to create one just for one function.

It will grow.  :-)

Let's not have Win32 specific functions in generic files, especially
when we already have a mechanism for isolating signal related code.

Andrew.