I then follow the instruction to generate the make files using CMake, like so:
cmake -G 'Unix Makefiles' /Path/To/LLVM-Repository
This fails to configure with the following error - what is going wrong?
CMake Error at tools/clang/CMakeLists.txt:480 (add_custom_target):
add_custom_target cannot create target "install-libclang-headers" because
another target with the same name already exists. The existing target is a
custom target created in source directory
documentation for policy CMP0002 for more details.