Bug#933629: hepmc3 FTBFS on arch-only: missing Build-Depends: doxygen for running dh_doxygen

[Helmut Grohne]

Source: hepmc3
Version: 3.1.1-1
Severity: serious
Tags: ftbfs

hepmc3 fails to build from source, because it unconditionally runs
dh_doxygen but lists doxygen in Build-Depends-Indep only. arch-only
builds are deemed to fail.

Helmut