Add CLANG/LLD/LLD to BROKEN_OPTIONS when building on non-FreeBSD

These tools require a bootstrap llvm-tblgen/clang-tblgen and that cannot
be built with the current make infrastructure: the config header is not
correct for Linux/macOS and we don't include the CMakeLists.txt in contrib
so we can't generate one that would be correct.

Reviewed By: emaste, imp, dim
Differential Revision: https://reviews.freebsd.org/D14245