I'm curious if there is any current effort to track packages not building under Clang/LLVM. FreeBSD switched as a default, and I've heard that Debian was considering a switch at one point. Gentoo seemed to have an effort to track packages, but it seems like it may have fallen off the radar.
There are some major blockers, like glibc, but the list already seems fairly small. Are there any formal plans for support Clang/LLVM as a system compiler going forward?