Set target_arch based on QT_ARCH for x86 and x86_64

This is needed when cross-compiling for the emulator.

Change-Id: I499c97df2deba8b91162c8f636bb5a25eba1bc29
Reviewed-by: Zeno Albisser <zeno.albisser@digia.com>
Update patches with fixes for the emulator and raspberry pi

Change-Id: I475941acdaa2581851f69199c0ecda7edddab389
Reviewed-by: Zeno Albisser <zeno.albisser@digia.com>