This is a spontaneous and verbatime log of a conversion with Boris Staletic @bstaletic from March, 24th 2018 on the pybind11 gitter. Thank you so much, Boris!
To confuse future readers, we decided to write down the discussion and I added typos and unnecessarily long sentences.
The issue came up with linking a CMake (library) target into a pybind11 module (in openPMD-api).