While trying to work on my pull request #108  I've run into a
stumbling block that is beginning to drive me nuts. I feel like I've
done something wrong, since I don't see anyone else talking about it,
but am at a loss as to what to do.
When the bootstrap runs it is crashing with `ld: symbol(s) not found for
architecture x86_64`. I've posted  the full build log. It was
generated with utils/build-script --llbuild --swiftpm > allout.txt 2>&1.
SwiftPM is on commit df7736e3962bfe183451d52b9b865b92f4f9ab26 (just want
to point out it does not include my WIP branch) and everything else
should be on its latest.
The crash is repeatable. I delete all the swift repos and clone them all
down and run the compile again and it crashes same place every time.
Someone please help me so I can feel a little less incompetent (or more
as the case may be).