Fix: Compiling Shader Builder.

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: blender/blender#106180

source/blender/gpu/CMakeLists.txt

@@ -800,6 +800,8 @@ if(WITH_GPU_BUILDTIME_SHADER_BUILDER)
     bf_blenlib
     bf_intern_ghost
     ${PLATFORM_LINKLIBS}
+    ${IMATH_LIBRARIES}
+    ${IMATH_LIBRARY}
   )
   target_include_directories(shader_builder PRIVATE ${INC} ${CMAKE_CURRENT_BINARY_DIR})