Stub out the functionality that cannot be supported that way.

If GL vertex shader clipping is supported (GLSL or NVvp), we currently
always calculate clipping results in the shader. They're gracefully
discarded by opengl, but we need 6 constants / uniforms to calculate
unused values.

Implement GetFileNameFromBrowse as an AW function.

We don't want to send WM_CANCELMODE or set the foreground window to the
desktop when a virtual desktop loses focus. It has its own focus independent
of X.

When explorer gets a take focus message, it tries to focus the foreground
window, but this doesn't work because set_focus can only focus windows in
the current process. We have to look for the focus window in the foreground
thread, not the current one, or we won't find the other process's windows.

Since the other process may crash at any time, causing its windows to be
destroyed, we also have to ignore the BadWindow error that will occur if that
happens at a critical time.

Revert "rpcrt4: The get_ranged_enum test doesn't work on Windows, so don't execute it for the moment.".

This reverts commit 81036cc51831db03f8e0eb03b5f74ae5099461cd.

rpcrt4: Replace sizeofs with FIELD_OFFSET in RPCRT4_BuildBindNackHeader to avoid relying on ANYSIZE_ARRAY being 1.

Not all cards support dynamic usage textures, and we don't actually need it.

Fixes Valgrind errors in various tests using RPC.

The parameter is a pointer to an array, so don't access it like it is
an array of pointers.