Known-size integer types

To enhance portability to bigendian, non-32-bit, non-glibc-based systems,
I've done some work to improve the squid integer-size-detection code,
and I'm asking for advice on how to better integrate this.

Currently some level of integration is done in config.h.in,
defining the num32 and u_num32 types.

What is almost done, and how I'd like to proceed.
- detection and definition of [u_]int{16,32,64}_t types,
  either at the support library level (glibc defines those)
  or in autoconf.h

What I'd like to do:
- add checks for other sources of known-length-types
  (such as glib.h for instance)
- create a new header (let's call it squid_types.h) that
  hides the details on exactly HOW those types are obtained
- alter config.h.in so that squid_types.h is included, and
  add some compatibility #defines for the num32 stuff.

WHY?
-The new stuff is more generic and portable
-The separate include file will be more self-contained and will
 be more easily available to helpers

Thoughts? Is my suggested roadmap OK with everybody?
If so, I think I can commit most of this stuff in a very short term.

-- 
	/kinkie