Sorry for not reporting it sooner. It looks to me like a GNU `as` bug: https://github.com/ClangBuiltLinux/linux/issues/1153#issuecomment-692265433 When I'm done with the three build breakages that popped up overnight I'll try to report it to GNU binutils folks. (We run an issue tracker out of https://github.com/ClangBuiltLinux/linux/issues, if your interested to see what the outstanding known issues are, or recently solved ones. We try to aggressively track when and where patches land for the inevitable backports. We have 118 people in our github group!)
