[ms-inline asm] Do not omit the frame pointer if we have ms-inline assembly.

If the frame pointer is omitted, and any stack changes occur in the inline
assembly, e.g.: "pusha", then any C local variable or C argument references
will be incorrect.  

I pass no judgement on anyone who would do such a thing. ;)
rdar://13218191

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175334 91177308-0d34-0410-b5e6-96231b3b80d8
Reinitialize the ivars in the subtarget so that they can be reset with the new features.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175336 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF] Add STN_UNDEF.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175338 91177308-0d34-0410-b5e6-96231b3b80d8