CMake files on macOS link to non-existent libtbb.12.8.dylib

Hi,

I want to compile an application (LibrePCB) which depends on OpenCascade. On macOS therefore I installed OpenCASCADE with Homebrew, which automatically installs the dependency tbb as well:

brew install opencascade

OpenCascade is then found by CMake when building LibrePCB. But then make fails because libtbb.12.8.dylib does not exist:

make[2]: *** No rule to make target `/usr/local/opt/tbb/lib/libtbb.12.8.dylib', needed by `apps/librepcb-cli/librepcb-cli.app/Contents/MacOS/librepcb-cli'.  Stop.

It seems that the installed CMake files of OpenCASCADE depend on a very specific TBB version, probably the TBB version installed while building OpenCASCADE(?). But if TBB has been updated to a later version in the mean time, the CMake files of OpenCASCADE will be broken because the referenced TBB version does not exist on the system anymore.

After a quick look, I found these lines in /usr/local/opt/opencascade/lib/cmake/opencascade/OpenCASCADEFoundationClassesTargets.cmake:

set_target_properties(TKernel PROPERTIES
  INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include/opencascade"
  INTERFACE_LINK_LIBRARIES "/usr/local/opt/tbb/lib/libtbb.12.8.dylib;/usr/local/opt/tbb/lib/libtbbmalloc.2.8.dylib"
)

# Create imported target TKMath
add_library(TKMath SHARED IMPORTED)

set_target_properties(TKMath PROPERTIES
  INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include/opencascade"
  INTERFACE_LINK_LIBRARIES "TKernel;/usr/local/opt/tbb/lib/libtbb.12.8.dylib;/usr/local/opt/tbb/lib/libtbbmalloc.2.8.dylib"
)

So there are indeed "hardcoded" versions for libtbb and libtbbmalloc.

My main question is now: Is this intended or a bug? If it's a bug, how to proceed? It seems I cannot open an issue in the bug tracker, so I hope somebody could pick this up. Thanks.

For context, here's the corresponding issue for the Homebrew package: Homebrew/homebrew-core/#129111