QT building applications for arm linux

ameise
hey guys, I got a little confused when it comes to QT and cross compiling
appliations for my arm-linux:

So I have a linux running on my AT91SAM9263-EK and an appropriate
filessystem including QT libs build via buildroot.

Also I have build QT-4.8 on my ubuntu.

Now I want to build an example application:

1. I created a makefile in an examples folder in QT on my ubuntu using
qmake; I used the given qmake.conf in mkspecs/qws/linux-arm-g++.

2. when executing make I get an error because it includes qatomic_i386.h
and the message "error: impossible constraint in 'asm'".
this header file does obviously not match to my arm toolchain.

my question:
how to configure Qt on my ubuntu to build Qt binaries for my embedded linux
on arm? Do I need to include any libs build by the arm toolchain?

any help is appreciated!

regards