Workaround missing G4persistency target bug in Geant4 11.2

cmake/CeleritasUtils.cmake

@@ -644,14 +644,30 @@ function(celeritas_get_g4libs var)
       set(_ext "-static")
     endif()
 
-    foreach(_lib IN LISTS ARGN)
-      set(_lib Geant4::G4${_lib}${_ext})
-      if(NOT TARGET "${_lib}")
-        message(AUTHOR_WARNING "No Geant4 library '${_lib}' exists")
-      else()
+    foreach(_shortlib IN LISTS ARGN)
+      set(_lib Geant4::G4${_shortlib}${_ext})
+      if(TARGET "${_lib}")
         list(APPEND _result "${_lib}")
+      elseif(_shortlib STREQUAL "persistency")
+        # Workaround for differing target names in 11.2.0,1 for G4persistency
+        # We do this here and not in FindGeant4 because we have no
+        # guarantee projects using Celeritas and Geant4 won't mess with target
+        # names themselves (and if we had to create a "celeritas::" target,
+        # we'd still have to specialize here).
+        list(APPEND _result Geant4::G4mctruth${_ext} Geant4::G4geomtext${_ext})
+        if(TARGET "Geant4::G4gdml${_ext}")
+          list(APPEND _result Geant4::G4gdml${_ext})
+        endif()
+      elseif(_shortlib STREQUAL "tasking")
+        # Same workaround for tasking, which was split between G4global and G4run
+        # from 11.1
+        list(APPEND _result Geant4::G4run${_ext} Geant4::G4global${_ext})
+      else()
+        message(AUTHOR_WARNING "No Geant4 library '${_lib}' exists")
       endif()
     endforeach()
+    # This avoids "ld: warning: ignoring duplicate libraries:"
+    list(REMOVE_DUPLICATES _result)
   endif()
   set(${var} "${_result}" PARENT_SCOPE)
 endfunction()