QNX subprocess bug

[Bob Bramwell <bbramwel@shaw.ca>]

I submitted an article about this a month or so ago but never saw it come 
around, so my apologies if this is old news to you.

The bug is showing up in emacs 21.2.1 on QNX 6.3.0.  It appears that process IDs 
  on QNX really occupy 32-bits.  Some of them are quite large.  This causes a 
problem in the subprocess package which uses an elisp integer (28 bits + type 
info - I think) to try to store the PID.  An added complication is that there is 
a cheap-and-cheerful "just stuff this value into this elisp int" macro which (in 
this case) has the effect of clobbering the type bits, ultimately resulting in 
what appears to be a garbage collector infinite recursion crash.

Obvious this problem could, in principle, arise on any system that uses 32-bit 
process IDs, and it seems to me rather sloppy programming to use such a 
shortcut, especially in such comparatively rarely executed code.

It looks as though there ought to be some way to rewrite the code with the 
integer represented as a kind of indirect object, but I don't feel qualified to 
do this without consulting The Experts.  Anyone wish to provide some guidance? 
I will gladly fix the problem given a few pointers.