zbar fails to cross build from source for multiple reasons. The
immediate failure is a failure to satisfy its host architecture perl
dependency as it conflicts with the build architecture perl interpreter
that is part of essential. I guess that the reason for depending on perl
was to build a perl extension module. This need is now satisfied via
perl-xs-dev and that package happens to also install perl:any.
Therefore, I suggest dropping the perl dependency.

Nextup, a Python extension module is being built. Depending on
python3-dev:any is not enough. An additional dependency on
libpython3-dev is needed. Then the extension build needs to be told
about the desired architecture via _PYTHON_SYSCONFIGDATA_NAME.

Last but not least, the g-ir-scanner fails for zbar. I am attaching a
patch for the first two problems and will report a separate bug for the
g-ir-scanner.

Helmut