Initial patch for x32 ABI support.

Add the x32 environment kind to the triple, and separate the concept of
pointer size and callee save stack slot size, since they're not equal
on x32.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173175 91177308-0d34-0410-b5e6-96231b3b80d8