FYI, quite a nice way of getting a consistent environment for testing these things is to do something like the following (this should work on any system with cvmfs installed):
source /cvmfs/sft.cern.ch/lcg/views/setupViews.sh LCG_94 x86_64-centos7-gcc8-opt
(I'm assuming you're in bash here)
You can obviously modify the LCG version and the platform etc. as you wish.
NB that for the above one you'll need to use C++17
One other nice feature of using LCG views to set the environment is that these LCG releases contain some of our dependencies, so we don't have to mess around building them ourselves necessarily. They seem to get automatically picked up by cmake - as least this worked for HepMC2 when I tried it just now.

I tried gcc 6.3.0 and the configure script has been modified to enable C++14, although the corresponding environment variable is still called CPP11.

@jback, I think you are still compiling with C++11 using old build system. We will need CMake as soon as we are removing EvtGen from LHCb repository, so lets review Tom's changes for that and merge that into master. Then we can rebase modernize branch from master to get CMake build system into it and by that it should be basically automatic as Tom put at least C++14 into that.

@jback, which version of g++ you use? I think we might need at least C++14 for code changes Gerhard did. Using g++ 6.2 should work, g++ 4 will definitely not.

LHCb repository uses report() for print statements while our version uses EvtGenReport(). Used the following sed-like commands to change these lines:

There are compilation problems, specifically private copy constructors in EvtItgPtrFunction and related classes, giving errors when auto and make_unique are used in EvtBtoXsgammaKagan, for example. Similar issues occur for
EvtRareLbToLll, EvtVubBLNP and EvtVubNLO. Could be compiler-version dependent?