Package: src:dpkg
Version: 1.22.21
Severity: important
Tags: sid forky
As you asked to file a separate bug report:
dpkg-dev/dpkg-buildpackage doesn't check the Build-Profiles syntax and
lets a package build fail.
llvm-toolchain-21 had used a syntax
Build-Profiles: <!pkg.llvm.noclang> + <!pkg.llvm.nolld>
which disabled the build of the binary packages having such a profile.
dpkg-buildpackage doesn't complain about that syntax. It should, and
fail the build instead of just not building packages with such a profile.