LLVMBuild.txt: Reformat.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205961 91177308-0d34-0410-b5e6-96231b3b80d8
LLVMBuild.txt: Add missing dependencies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205962 91177308-0d34-0410-b5e6-96231b3b80d8