wined3d: We only care is a sampler is sampled at all in device_map_vsamplers(), not the specific type.

msvcrt/tests: Load __mb_cur_max and _mbctype dynamically since they may not be available to link against.

That bug was uncovered by Henri's change of the bitfield sizes.

It makes the code more readable and will help us to merge the ALPHAOP
and COLOROP code.