scons/windows: Support build with LLVM 10.

LLVM engine component contains 2 new libraries, LLVMCFGuard and LLVMTextAPI.
Without them build fails like in this run: https://ci.appveyor.com/project/Alexpux/mingw-packages/builds/32102425/job/wkmb4gimfqkkb3cg

Cc: <mesa-stable@lists.freedesktop.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4521>
1 file changed