The few options are niche. They solved a problem which was traditionally solved
with more shell commands. Due to limitation, they are no longer used by Fuchsia
and they don't appear to be used elsewhere (checked with Google Search and
Debian Code Search). So delete them without a transition period.
Removal announcement: https://lists.llvm.org/pipermail/llvm-dev/2021-February/148446.html
(I am trying my best to find the dark web users.)