[oe] Problem with qmake2 and native sdk

[Philip Balister]

I building PyQwt on an omap3 suing the qt native sdk. This leads to the 
following message:

Could not find mkspecs for your QMAKESPEC(linux-g++) after trying:
         /home/balister/oe/tmp/sysroots/x86_64-linux/qt4/mkspecs

I can work around this by editing the PyQwt configure.py file to use the 
full path to the linux-g++ spec file, but it would be nice if this 
worked out of the box.

Does anyone know how to change the default spec file path in qmake2? 
I've looked at the recipe and nothing jumps out at me to try.

Philip