Merge changes from topic \'merge_dev_master\'
am: 197cdc4

* commit '197cdc48df63e008207c329704082306fd43c18a':
  Support building 64-bit windows binaries for Clang.
  Build libclangToolingCore.a for extra host tools.
  Add -fnative-half-arguments-and-returns
  Revert "Handle __fp16 natively if HalfArgsAndReturns langopt is set"

Change-Id: Id0f6be620a1fb403e0953f3e180f3dc400d912a8