Extended Description
First reported here: https://reviews.llvm.org/D69825#1831258
Worked around with:
https://reviews.llvm.org/rGc38e42527b21acee8d01a016d5bfa2fb83202e29
https://reviews.llvm.org/rGe174da447c180b586719cb28f7bd556e30625762
Later on in D69825 it's suggested that if we can't fix this properly, maybe -emit-interface-stubs should imply -fno-integrated-cc1
Filing this to keep track of the issue, especially for the 10.0.0 release.