cmt/requirements: update for LCG_64 (AtlasHepMC-00-00-20)

External/AtlasHepMC/cmt/requirements

+package AtlasHepMC
+
+author  Cano Ay <aycano@mail.cern.ch>
+
+# The ATLAS Simulation/HepMC will be (more or less is) replaced by the LCG HepMC package.
+# Because of a package name clash this package is named External/AtlasHepMC and it points directly to the LCG HepMC package. 
+# Currently the most recent Simulation/HepMC points to this package.
+# Once this replacing has taken place Simulation/HepMC should not be used anymore
+
+use ExternalPolicy ExternalPolicy-* External
+use LCG_Configuration v*
+
+macro HepMC_home "$(LCG_external)/HepMC"
+macro hepMC_native_version "$(HepMC_config_version)"
+macro HepMC_native_version "$(hepMC_native_version)"
+macro AtlasHepMC_native_version "$(hepMC_native_version)" 
+macro AtlasHepMC_lib "$(HepMC_home)/$(HepMC_native_version)/$(LCG_system)/lib"
+
+macro HepMC_linkopts         "-L$(AtlasHepMC_lib) $(notAsNeeded_linkopt) -lHepMC $(asNeeded_linkopt) "
+macro HepMC_IO_linkopts      "-L$(AtlasHepMC_lib) -lHepMCfio"
+macro AtlasHepMC_linkopts    "$(HepMC_linkopts)"
+macro AtlasHepMC_IO_linkopts "$(HepMC_IO_linkopts)"
+
+include_path none
+include_dirs $(HepMC_home)/${HepMC_native_version}/$(LCG_system)/include 
+
+macro AtlasHepMC_export_paths \
+       "$(HepMC_home)/$(hepMC_native_version)/$(LCG_system)" 
+
+# This is required to override the symlinks in the LCGCMT InstallArea
+apply_pattern declare_installed_libraries dir=$(HepMC_home)/$(hepMC_native_version)/$(LCG_system)/lib
+