linux-g++: QMAKE_TARGET.arch = $$QMAKE_HOST.arch
linux-g++-32: QMAKE_TARGET.arch = i686
linux-g++-64: QMAKE_TARGET.arch = x86_64
-linux-g++-64: QMAKE_TARGET.arch = x86_64
win32-g++-cross: QMAKE_TARGET.arch = $$TARGET_PLATFORM
# for boost 1.37, add -mt to the boost libraries