Reported by Christoph von Wittich.

We need GL_ARB_instanced_arrays to be able to take the fastest path and
that's already checked in draw_primitive.  Note that
GL_ARB_instanced_arrays provides glDrawElementsInstanced if
GL_ARB_draw_instanced is not supported so we don't need to explicitly
check for the latter.

Wined3d doesn't actually require the GLX extension for multisampling
at this point (while it does require FBOs).

Games created by GameMaker modify the FPU control word to enable
division by zero exceptions. The game Risk of Rain, which is written
with GameMaker, furthermore sets fogstart == fogend, which triggers an
exception when the GL driver attempts to calculate 1 / (fogend -
fogstart). This test adds some evidence that we are not supposed to
temporarily restore the FPU CW if D3DCREATE_FPU_PRESERVE is used.