[xproto: PATCH] Xmd.h: amd64-x32 ABI defines sizeof(long) == sizeof (void*) == 4

[Mark Kettenis]

> From: "Lu, Hongjiu" <hongjiu.lu at intel.com>
> Date: Wed, 28 Dec 2011 14:34:09 +0000
> 
> __AMD64__ is defined when 64bit x86 instruction set is used,
> which is true for x32. The difference is x32 doesn't define
> __LP64__.

Chapter 7, "Development Environment", of the AMD64 ABI (the non-x32
version) does not list __LP64__ as a predefined pre-processor symbol.
As far as I'm aware, it's just a GCC convention to define __LP64__ for
platforms that use the LP64 programming model, and even GCC didn't do
so very consistently in the past.