Some small hacking opportunities :)

[Simon Richter <sjr@debian.org>]

Hi,

as I don't know anything about perl and severely lack time at the
moment, I thought I might ask around if anyone feels motivated to hack
something:

1. #558095: The "minimal" implementation laid out in the bug report is
   just that, minimal. It would be better to have proper support for
   handling qualified build dependencies, at least in dpkg. Fortunately,
   the only place that requires significant changes appears to be
   dpkg-checkbuilddeps.

   Basically, this command needs -a and -t options similar to
   dpkg-architecture, and the resolver adapted to check whether the
   package in question is installed for the proper architecture,
   according to the table on https://wiki.ubuntu.com/MultiarchCross . As
   the relevant query interface has not really been defined, this means
   pes^H^H^Hcollaborating with the dpkg developers.

2. #539038: The patch is somewhat outdated and does not quite conform to
   the wishes of the dpkg maintainers. Forward-porting is simple,
   adapting it to use the tilde notation rather than the "x-" prefix is
   too, but determining the missing values for the environment rather
   than writing "unknown" is somewhat difficult (and not always
   possible, but we ought to at least try).

   I am wondering if appending the tilde would be somewhat safer to
   avoid shell expansion; if it should indeed go to the front,
   dpkg-architecture should have an appropriate test here.

3. #537645: This patch is outdated as well, and is in severe need of
   deuglification. Due to the peculiar way dpkg-cross passes variables
   between the DpkgCross perl module and the frontend binary, this is
   most suitable for someone who understands variable scoping
   blindfolded.

4. #545464: Another patch that is somewhat outdated and does not really
   work. What *should* happen is that any file in
   /usr/{include,lib}/$triplet is passed through with the same path, so
   dpkg-cross just adds co-installability to those packages for systems
   with pre-multiarch dpkg.

5. It would also be nice to have a dpkg-cross mode in which an empty
   arch-dependent -cross package is generated that depends on the real
   -dev package and that has a slightly higher version number (append
   "+~multiarchtransition". A multiarch capable package manager would
   then prefer this package, while dependencies from pre-multiarch
   -cross packages could be satisfied.

All of these should be fairly simple for anyone proficient in perl. For
me, they aren't. :/

   Simon