add trivial support for passing label definitions through the MCStreamer.

This is suboptimal in several aspects, see the commented out assertion.
I need to talk to Daniel about this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74057 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed