"Argument unused caused failure" build failure(s) — clang 12.0.1

Unknown or unused arguments triggers errors with -Werror:
clang -Werror -ggdb3 foo.c
PackageVersionSupposed error messageFull log Bug report
acm 6.0+20200416-1clang: error: argument unused during compilation: '-fmax-errors=99' [-Werror,-Wunused-command-line-argument] Log 740019
acpica-unix 20200925-6clang: error: argument unused during compilation: '-pie' [-Werror,-Wunused-command-line-argument] Log
python-pyxattr 0.7.2-1clang: error: argument unused during compilation: '-specs=/usr/share/dpkg/no-pie-compile.specs' [-Werror,-Wunused-command-line-argument] Log
skiboot 6.7.1+dfsg-1clang: error: argument unused during compilation: '-specs=/usr/share/dpkg/no-pie-compile.specs' [-Werror,-Wunused-command-line-argument] Log

4 errors