The LLVM project no longer supports building with configure & make.

[gefei-li]

When makefile run into line
'@$(CD) $(DIR_BUILD) && ../$(DIR_LLVM)configure --enable-optimized'
it will output:

'The LLVM project no longer supports building with configure & make.
Please migrate to the CMake-based build system.
For more information see: http://llvm.org/docs/CMake.html'.

I guess maybe the version of 'ClangKit/LLVM/Source/llvm' is not latest?