At Jim Grosbach's request detemplate Object/MachO.h.

We are still able to handle mixed endian objects by swapping one struct at a
time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179778 91177308-0d34-0410-b5e6-96231b3b80d8
Fix comment. Patch by Stephen Lin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179780 91177308-0d34-0410-b5e6-96231b3b80d8