Instead of sprinkling '!ios' all around the various modules. This is
a bit more fine grained than the CFG_NOBUILD_PARTS += "tests" that we
had in configure.
Change-Id: I6ca2e5df118dfc0bb5d7b8495a3543f51dc0fa30
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>