This happened to work because most cards have the same amount of
pshader and vshader constants, but for some reason this doesn't hold
true on this macbook pro here, which lead to a crash due to heap
corruption

Some drivers(the open source ones most notably) cannot satisfy all
possible D3D formats. This doesn't mean we should fall back to the
emergency fallback instantly. Instead, try to loosen the requirements
step by step.

Also follow the naming convention for the 'xxx-config' variables.

shell32: Avoid usage of undefined xdg_results variable, since XDG_UserDirLookup() always corrupts it.

This reverts commit 3cbd9639.