[gn build] Add build files for lib/CodeGen, lib/Transforms/..., and lib/Bitcode/Writer

Differential Revision: https://reviews.llvm.org/D55454


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348667 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed