lld (build with configur and make) Enable build

r210177 added Makefiles to the lld project. 
This revision enables the automatic build of lld when the sources are found in tools/lld.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210245 91177308-0d34-0410-b5e6-96231b3b80d8