Allow include of G4 headers with or without 'Geant4/' prefix

The standard deployment of Geant4 required that Geant4 headers are included without the Geant4/ prefix (although they get installed in include/Geant4) so the merge of !79 (merged) requires that the client code is adapted.

This MR modifies the build of the current Geant4 (pre !79 (merged)) so that client projects (Gauss and Gaussino) can already switch to the new #include policy.

/cc @gcorti @mimazure @dpopov

mentioned in merge request Gauss!807 (merged)

changed target branch from master to Sim10

added 51 commits

• 7ad23318...49247288 - 50 commits from branch Sim10
• 8217ff99 - Allow include of G4 headers with or without 'Geant4/' prefix

Compare with previous version

changed the description

@gcorti, as discussed, I switched from master to Sim10.

added all-slots label

mentioned in merge request lhcb-core/LHCbNightlyConf!768 (merged)

removed all-slots label

added 1 deleted label

added lhcb-gaussino-prerelease label

• [2022-01-29 00:12] Validation started with lhcb-gauss-dev#3032
• [2022-01-29 00:18] Validation started with lhcb-gaussino-prerelease#17
• [2022-01-30 00:03] Validation started with lhcb-gauss-dev#3033
• [2022-01-31 00:03] Validation started with lhcb-gauss-conf#464
• [2022-01-31 00:04] Validation started with lhcb-gauss-gen3-dev#106
• [2022-01-31 00:04] Validation started with lhcb-gauss-gen2-dev#576
• [2022-01-31 00:04] Validation started with lhcb-gauss-dev#3034
• [2022-01-31 00:05] Validation started with lhcb-gauss-lamarr#512
• [2022-01-31 00:08] Validation started with lhcb-sim10#1059

@clemenci This works fine in ~lhcb-gauss-dev (https://lhcb-nightlies.web.cern.ch/nightly/lhcb-gauss-dev/3033/) where Gauss!807 (merged) is taken, and it also works when Gauss!807 (merged) is not taken like in lhcb-gaussino-prerelease (https://lhcb-nightlies.web.cern.ch/nightly/lhcb-gaussino-prerelease/17/)

Changing label to all-slots as it can be picked up everywhere.

I understand this !MR is a pre-requisite to the work in !79 (merged), correct?

added all-slots label

removed 1 deleted label

Gauss!807 (merged) is a prerequisite for !79 (merged), while this backward compatible change makes it possible to test Gauss!807 (merged) on an old style build of Geant4.

The order is actions I had in mind is

• merge this
• merge Gauss!807 (merged)
• validate !79 (merged)
• merge !79 (merged)

assigned to @dpopov

mentioned in commit f8b6ccfc

merged

resolved all threads

removed all-slots label

removed lhcb-gaussino-prerelease label

unassigned @dpopov

mentioned in issue #2 (closed)