dh-builtusing planned change affects condor gnupg2 matrix-synapse

[Nicolas Boulenguez <nicolas@debian.org>]

Hello.

I intend to change the dh-builtusing debhelper plugin in a way that
would affect the 3 packages in the subject.

A pattern like ${dh-builtusing:librust-*-dev} in the control file is
first searched in Build-Depends fields (generating a relation per
match).  If no match is found, all installed packages are searched.

As said in the manual page, this fallback trick was intended for
debhelper plugin authors.  Time has passed, no plugin author seems
interested, and this fallbacks affects build reproducibility.

I intend to emit a deprecation warning when it is required, then one
day replace it with an error.

Can 'condor' add libc-dev-bin to Build-Depends (or -Arch)?
Probably yes, it already depends on it via build-essential.

Same question for 'gnupg2'.

Can 'matrix-synapse' add librust-base64-dev, librust-blake2-dev and so
on to Build-Depends?  Else, could you please describe your needs?

Thanks.