Driver: Add majority of driver-driver implementation.
 - Compare to driverdriver.c if bored; not completely fair since the
   driver gets a bit more code in other places to handle binding archs
   (for Xarch) but not completely unfair either.

Fear not, extra Action classes will have a happy home for their
vtables soon.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66817 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed