Merge branch 'hepmc3_nightly_fixes_01022021_part_1' into 'master'

hepmc3 nightly fixes 01022021 part 1

See merge request atlas/athena!40256

Generators/GeneratorObjects/CMakeLists.txt

@@ -27,6 +27,8 @@ else()
                         GeneratorObjects/McEventDict.h
                         GeneratorObjects/selection.xml
                         LINK_LIBRARIES GeneratorObjects RootUtils )
+  add_library( HepMC3rootIO SHARED src/dummylibHepMC3rootIO.cxx)
+  set_target_properties (HepMC3rootIO PROPERTIES SOVERSION 3)
 endif()
 
 # Install a dummy rootmap file to suppress loading the rootmap from hepmc3,

Generators/GeneratorObjects/src/dummylibHepMC3rootIO.cxx

+/*
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+*/
+
+void TriggerDictionaryInitialization_libHepMC3rootIO() {
+  }