This morning XQuartz
reminded me that there's a new version (2.8.2) to which to
upgrade. Alas, because versions later than 2.7.11 remove libXp,
XEphem won't compile on macOS with a modern XQuartz. libXp
dependence in XEphem should be removed and replaced with a
modern lib for any missing functionality; otherwise, we're at
risk of being left behind.
Unfortunately, it's way
beyond my skill set to even analyze the code and figure out
where such functionality is used.
XEphem 4.0.1 available via MacPorts for x86_64 macs:?