Fix issue with HEPMC3

Thanks for this MR!

I notice, however, that even if the use of HEPMC3 is ruled by an option, there are lines where the HEPMC3 libs and headers are added to the build without a switch:

https://gitlab.cern.ch/GeoModelDev/GeoModel/-/blob/FixHEPMC3CmakeIssue/FullSimLight/CMakeLists.txt#L206-216

Do we probably want to make them under the switch, too?

I think this is o.k. as is, as the HEPMC3_... variables will be empty if HEPMC3 isn't found.

Hi @boudreau, in relation to your comments on #71 this looks absolutely fine to me.

Thanks Ben.. Ric, please go ahead and make the changes you propose so we can close this MR and the related issue.

added 3 commits

• 26dfe79f - Make use of HepMC3 OFF by default
• 81bf9cdd - Add a message to the user when HepMC3 support is OFF
• d2b92c61 - Link to HepMC3 if it is used/enabled

Compare with previous version

OK, I moved the libs/headers under the same switch.

Also, I added to the FSL main window a message to the user, to let them know when the support for HepMC3 is disabled:

added 1 commit

• 511bbe87 - Fix message to the user when HepMC3 is ON

Compare with previous version

OK, tested on macOS Ventura: everything looks OK.

marked this merge request as ready

enabled an automatic merge when the pipeline for 511bbe87 succeeds

OK, I set it as auto-merge as the CI completes

mentioned in commit b1169820

merged

mentioned in issue #71