wined3d: Rewrite surface_modify_location() on top of surface_validate_location() and surface_invalidate_location().

Otherwise invoking winegcc on any platform where our first guess at
the link options fails results in a lot of confusing error messages.

This stops the tested gcc command from issuing a warning on Solaris.

It's not worth printing a FIXME for every VARTYPE we don't happen to
list in the switch statement.

Sizes of textures and stand-alone surfaces must be multiples of the
format's block size for DXTN formats. Since we create a texture for
everything (except in ddraw), this check also takes care of stand-alone
surfaces.

user32/tests: Test to show that SendMessage/PostMessage don't force caller activation context on window thread.

ddraw: Introduce a helper function for initializing a D3DDEVICEDESC structure from a D3DDEVICEDESC7 structure.

It's not necessarily clear to me that one is better than the other here, but
this is what we returned in the old GL fixed function implementation of the
D3D fixed function vertex pipe, and apparently EverQuest depends on this.

This fixes a regression introduced by commit 2014141a.