Predefine IB_DESIGNABLE and IBInspectable macros. <rdar://problem/17441860>

These macros are used as markers for Interface Builder and need to be defined
to empty strings since they have no impact on the code.

Patch by Ted Kremenek.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215259 91177308-0d34-0410-b5e6-96231b3b80d8
Add predefined macros to identify x86_64h architectures.

Patch by Jim Grosbach.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215260 91177308-0d34-0410-b5e6-96231b3b80d8