Due to changes in the build environment shader_builder wasn't able to
compile on macOs. This patch reverts several recent changes to CMake files.

* dbb2844e
* 94817f64
* 1b6cd937

The idea is that in the near future shader_builder will run on the buildbot as
part of any regular build to ensure that changes to the CMake doesn't break
shader_builder and we only detect it after a few days.

Pull Request: https://projects.blender.org/blender/blender/pulls/115929