Such support was disabled upstream.

Detected by Lintian's maintainer-script-without-set-e check.

Seems like this has been our intent but was not updated that much recently.

The makecd handler checks if those tools are installed, sure, but it actually
does not use these. Since its development has been stalled for years, we can
safely ignore the possibility of this handler starting to use such tools in the
near future.

This makes it easier to track and understand changes using Git
(i.e. git blame for the masses).

Sort Suggests lexically while I'm at it.

This makes it clear what package(s) one must install in order to use any given
handler.

The devscript package's long description served as an example of how we can deal
with shipping that many tools and only suggesting their individual dependencies,
without going through the overhead of shipping every single handler in its own
binary package.

... after having carefully read the upgrading checklist.

This makes it easier to build packages using git-buildpackage
since our branches setup is not the default one.

... after having carefully read the upgrading checklist.

add versioned build dependency on debhelper 5. version 4 would work, but the recommended practice is to always declare an explicit versioned dependency on debhelper equal to or greater than the compatibility level used by the package. We are using compat level 5

virtual-package-depends-without-real-package-depends can be resolved by adding a depends on bsd-mailx which is the real package that mailx transition depends on