bug#4643: two different definitions for catchlist in eval.c and alloc.c

[Dan Nicolaescu]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

  > >> Here's a patch that fixes this problem by moving the definition in a
  > >> separate file included in both places.
  > >> 
  > >> OK to check in?
  > 
  > > Ping.
  > 
  > I agree on the idea, but I don't want a new file just for that
  > declaration, so please move it to some existing file instead.

The catchtag structure definition needs a #include <setjmp.h> to precede it.
We don't include setjmp.h in many places, so it will need to be
added... 
I don't see any existing header that would be a good match (other than lisp.h).
So please suggest where to add it.