To update pythia8.240 into 7_1_X to make a special release

[qliphy]

Replacing #6549
This should be the minimal change to update Pythia8 to 240 in CMSSW_7_1_X, as requested by PdmV/GEN.

[cmsbuild]

A new Pull Request was created by @qliphy (Qiang Li) for branch IB/CMSSW_7_1_X/stable.

@cmsbuild, @smuzaffar, @mrodozov can you please review it and eventually sign? Thanks.
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[qliphy]

please test

[cmsbuild]

-1

Failed Tests: Build
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-ba5df9/12593/summary.html
COMMIT: 7abaeb9
CMSSW: CMSSW_7_1_X_2021-01-24-0000/slc6_amd64_gcc481
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmsdist/6604/12593/install.sh to create a dev area with all the needed externals and cmssw changes.

Build

I found compilation error when building:

>> Compiling  /build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/src/PTFilterHook.cc 
>> Compiling  /build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/src/Py8GunBase.cc 
>> Compiling  /build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/src/ResonanceDecayFilterHook.cc 
>> Compiling  /build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/src/Py8InterfaceBase.cc 
In file included from /build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/src/MultiUserHook.cc:2:0:
/build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/interface/MultiUserHook.h:439:8: error: 'bool MultiUserHook::doChangeFragPar(Pythia8::StringFlav*, Pythia8::StringZ*, Pythia8::StringPT*, int, double, std::vector)' marked override, but does not override
   bool doChangeFragPar( Pythia8::StringFlav* flavPtr, Pythia8::StringZ* zPtr, Pythia8::StringPT* pTPtr, int idEnd,
        ^
/build/cmsbld/jenkins/workspace/ib-run-pr-tests/CMSSW_7_1_X_2021-01-24-0000/src/GeneratorInterface/Pythia8Interface/interface/MultiUserHook.h:449:8: error: 'bool MultiUserHook::doVetoFragmentation(Pythia8::Particle)' marked override, but does not override
   bool doVetoFragmentation( Pythia8::Particle part) override {
        ^


[smuzaffar]

@qliphy , I guess we also need a backport of cms-sw/cmssw#25602 ( adapt Pythia8Interface to pythia8 240 ) to go along with this update

[qliphy]

merge