This should fix grass interactions on Breath of the Wild on Vulkan.
It is currently untested against validation layers.
Nvidia's Windows 443.09 beta driver or Linux 440.66.12 is required for
now.
Reduces some header churn and reduces rebuilds when some header
internals change.
While we're at it we can also resolve a missing include in buffer_cache.
Nvidia's driver defaults invalid enumerations to GL_CLAMP. Vulkan
doesn't expose GL_CLAMP through its API, but we can hack it on Nvidia's
driver using the internal driver defaults.
The OpenGL spec defines GL_CLAMP's formula similarly to CLAMP_TO_EDGE
and CLAMP_TO_BORDER depending on the filter mode used. It doesn't
exactly behave like this, but it's the closest we can get with what
Vulkan offers without emulating it by injecting shader code.