Bug#793554: lintian: Please warn on unnecessary dpkg-architecture invocations

[Guillem Jover <guillem@debian.org>]

Package: lintian
Version: 2.5.34
Severity: wishlist
Control: block 793404 by -1

Hi!

There are many packages (by my count from codesearch ~450) that are not
taking advantage of the fact that dpkg-architecture variables are
pre-initialized in the environment when running under dpkg-buildpackage,
when they use ‘=’ or ‘:=’. It would be nice to warn on those as that
should shave off some build time, when they switch to use ‘?=’.

Warning on something like:

  /DEB_(HOST|BUILD|TARGET)_(ARCH|MULTIARCH|GNU)[A-Z_]* *:?=/

on debian/rules or any of its sources files from the same source
package, might do it.

Thanks,
Guillem