Release blocker

The changes for Issue7211 to support 64-bit kevent ident fields
in 64-bit builds cause compile errors on those OS X multi-arch
builds which include both 32-bit and 64-bit variants.

Problem is reproducible by this simplified build config:

   configure --with-universal-archs=intel --enable-universalsdk=/
   make

To support C data types which vary between 32-bit and 64-bit builds,
Include/pymacconfig.h does some magic conditional type definitions
overriding the standard values derived from autoconf configure
processing.  Previously, SIZEOF_UINTPTR_T was not referenced in
the Python source; now that selectmodule.c uses it, it needs
to be added to pymacconfig.h.  The attached patch does that.

Although the select changes were only added to trunk (r76108)
and py3k (r76111), it would be better to apply this patch to the
maintenance branches as well in the event something else gets
added or backported to them.