Since version 4.9.4 geant provides new installation system. These changes are included in new ebuilds, which by addition don't provides any environment variables for latest geant installations (newer than 4.9.4). But many other applications using (and compatible with new) geant4 still use old variables such as G4INSTALL, G4SYSTEM, etc. Geant4 package provides backward compatibility shell script located in /usr/share/geant4/configure/geant4-xxxxx.{sh,csh} (where xxxx is geant minor version + patch version number) which set environment for other applications. Maybe Gentoo science-team can consider putting this script into /etc/profile.d location to create correct environment for Geant4, or at least, to print info message by ebuild, that sourcing of this script may be required for some other applications.
No one in Gentoo team is using Geant, we do it as a service for the users. If one provides such a profile file, I would be happy to commit it. Thanks!
A message for the user to indicate scripts for backward compatibility has been added. Re-open if you need more.
