[GsoC] Swift debugging support on Linux

Hi Adrian, sorry for the delay.

I created a PR against swift/master here.

There's a conflict between my branch and swift/master-next though. master-next doesn't have the methods GetUseSwiftClangImporter and GetUseSwiftDWARFImporter, only GetUseDWARFImporter. Should I adapt my code to work with the current version of master-next? Or should I open a open that can't be merged currently?

[I'm just going through my inbox] were we able to bring this to a conclusion or are you still waiting on input from me?

We finished this already :grin: