IMath is required for building with vulkan. This patch adds
dependencies to shader_builder for now.
Currently there is a difference between windows and other OS's in
which variable the library is stored. Might be because imath isn't
a direct dependecy. As this is a compilation error I did the quickest
solution and check with platform module what would be the best solution.
Pull Request: https://projects.blender.org/blender/blender/pulls/106180
0a4b5eb73e