Blender Git Loki

Cycles; Make baking a feature-specific option

This means render devices now might skip building baking kernels in cases when
only actual render-related functionality is used.

For now it's only implemented for OpenCL split kernel device and mainly needed
to work around some compiler-specific bugs which crashes on building the kernel.

Using OpenCL for baking might still crash the driver, but at least there is now
higher probability of that GPU will be usable to render the scene.

Real fix should actually be done in the driver side.