[Qt-interest] pure-54bit linux and qmake

[sibu]

Greetings,

I  use  a  computer with the following features:
cpu -amd64(2 cores)
os-prog: linux 64bit only GCC4.4.2 (kernel2.6.34), qt-X11opensource-4.6.2

I am experiencing difficulty compiling qt-webkit. (it is having difficulty 
locating the X11/Xlib.h  needed by TestNestcapePlugin.cpp)   I had a look at 
the  directory containing the makespecs  and noticed  that for 64 bit builds  
it is a multilib setup  (~/lib and l~/ib64).  

QUESTION:
A----  is there a makespec for pure 64-bit linux builds (I only have /~/lib)
B------if A is  positive could   someone tell   how to fetch it and use it    
please?
C-----if A is negative is is  possible to merge 
~mkspecs/common/{linux.conf&g++.conf} into a ~/~/pure64-linux.conf and would 
the same qplatformdefs.h be sufficient?
D----if C is positive   how does one invoke qmake to use the new ~/~/pure64-
linux.conf   spec?

sincerely
sx