[Pkg-gmagick-im-team] Bug#856601: libmagickcore-dev is wrongly marked Multi-Arch: foreign

[Helmut Grohne]

Package: libmagickcore-dev
Version: 8:6.9.7.4+dfsg-1
Severity: important
User: helmutg at debian.org
Usertags: rebootstrap
Control: affects -1 + src:hhvm src:nip2 src:vips src:inkscape src:performous src:k3d src:synfig src:synfigstudio src:zbar src:dx src:emacs24 src:gem src:gst-plugins-bad1.0 src:imview src:pstoedit src:rss-glx src:visp

libmagickcore-dev is marked Multi-Arch foreign. Its main functionality
comes from libmagickcore-6.q16-dev, as it is a dependency package. The
latter is Multi-Arch: same however. If a package Build-Depends on
libmagickcore-dev, it expects a host architecture library, but due to
the Multi-Arch: foreign marking it will receive the build architecture
library. Thus its dependency will be formally satisfied, but the
supposed functionality is missing.

Instead, libmagickcore-dev needs to pass the architecture constraint
down to its dependency libmagickcore-6.q16-dev. The only[1] way to
achieve that is to turn libmagickcore-dev Architecture: any, Multi-Arch:
same.

Due to a number of wicked[2] reasons, this causes the affected packages
to be unable to satisfy their cross build dependencies.

This problem likely also applied to other dummy packages such as
libmagickwand-dev.

Helmut

[1] In theory, one could solve the famous "multiarch interpreter
    problem" instead.
[2] Interpret http://bootstrap.debian.net/cross_all.html for details.