From Axel:

Fix to the previous fix for win32gcc:
-mtune is new for 3.3. So we'll have to wait until nobody is
using 3.2 anymore. But then -mtune is really nice, optimizing things to
be run on pentium, without requiring a pentium.


git-svn-id: http://root.cern.ch/svn/root/trunk@13327 27541ba8-7e3a-0410-8455-c3a389f83636