Backport ThinLTO LLVM 5 fixes#45301

Merged

bors merged 2 commits intorust-lang:masterfrom

ishitatsuyuki:llvm5-backport

Oct 19, 2017

Commits on Oct 17, 2017

Update ThinLTO for LLVM 5

alexcrichton
authored and
ishitatsuyuki
committed

Commits on Oct 19, 2017

Update ThinLTO (internalization) for LLVM 5
ishitatsuyuki
committed