Add CompilerInstance, and starting moving clang-cc to it.
 - The design philosophy is in the CompilerInstance doxyment, if you don't agree
   with it now would be a good time to speak up.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@87078 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed