iminuit is an external Python interface to the Minuit2 C++ code,
which can be compiled standalone without the rest of ROOT. iminuit
has recently seen a boost of development which culminated in the
latest 1.3 release and will join the Scikit-HEP project in this year.
To simplify Minuit’s use as a standalone CMake package, for projects
like iminuit and GooFit, a new standalone build system
was implemented for Minuit2, and has been
included in the latest release of ROOT. This system uses modern CMake
patterns, and lives in a peaceful coexistence with the ROOT build
system. The production of source packages is handled without external
scripts, and the system even supports building from inside ROOT.
Integrating this into the ROOT source and build system provided several
challenges, with some interesting solutions that will be shown.