Minor fixes

This is just to fix a couple of minor annonyances:

• Geant4 can be build with Ninja now, so no reason to disable it
• we can build without setting $CMTCONFIG so relying on it is a bad idea
• somebody had the clever idea of adding git to the LCG stack, breaking the compilation in dev3/4, so I had to filter it away

/cc @kreps @adavis @gcorti

added lhcb-lcg-dev3 lhcb-lcg-dev4 labels

assigned to @dpopov

I've just checked building it locally, everything compiles without troubles but there are quite a few new warnings, mostly suggest-override in our tests, I'll need to fix those.

However I ran into a problem with Python while checking that our G4 tests work -- it is same old extra line in the build/config/{project_name}-build.xenv with LbEnv path (which should be filtered out but still persists?). Removing it fixes the problem and our *.py tests run ok.

   <env:prepend variable="PATH">${LCG_releases_base}/LCG_97a/Python/2.7.16/x86_64-centos7-gcc9-opt/bin</env:prepend>
-> <env:prepend variable="PATH">/cvmfs/lhcb.cern.ch/lib/var/lib/LbEnv/1020/stable/linux-64/bin</env:prepend>
   <env:prepend variable="PATH">${LCG_releases_base}/LCG_97a/ROOT/v6.20.06/x86_64-centos7-gcc9-opt/bin</env:prepend>

@clemenci this does not happen in the nightly builds, right?

It's not a problem in the nightlies as we still use a Python 2 installation of LbEnv.

The bug has been fixed long ago in LbEnv-testing, but somehow it was never promoted to stable (@cburr?).

Stable is only updated when someone chooses to do it by hand and I haven't had a reason to since late September. Or are you saying the manual script isn't working?

(I plan to propose getting rid of this manual step as part of LBCORE-1963 but that hasn't been a priority for me yet.)

I was just wondering why this bug is still a thing, this explains it. It's not a huge problem since it is clear how to get around it.

But may not be clear for someone who is new or wants to get involved by testing on lxplus. I think we should minimize the number of "special cases" and push it to stable, no?

• [2020-12-05 00:34] Validation started with lhcb-lcg-dev4#1484
• [2020-12-05 02:31] Validation started with lhcb-lcg-dev3#1470

merged

mentioned in commit 1d85245c

resolved all threads