HepMC3 acinclude fix (rel-2-2-10)
acinclude.m4 sets the paths hard-coded and by default assumes HepMC3 is compiled with ROOT support, which is generally not the case. THis MR fixes this by getting all flags and paths from HepMC3-config instead.
acinclude.m4 sets the paths hard-coded and by default assumes HepMC3 is compiled with ROOT support, which is generally not the case. THis MR fixes this by getting all flags and paths from HepMC3-config instead.