build: MCConfigurator needs FairRoot::FastSim

So only build it, if FairRoot::FastSim is available.

Author: ChristianTackeGSI

fairroot/CMakeLists.txt

@@ -1,5 +1,5 @@
 ################################################################################
-#    Copyright (C) 2023 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    #
+# Copyright (C) 2023-2024 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH  #
 #                                                                              #
 #              This software is distributed under the terms of the             #
 #              GNU Lesser General Public Licence (LGPL) version 3,             #
@@ -40,7 +40,8 @@ else()
   message(STATUS "eventdisplay will not be built, because ROOT has no opengl support.")
 endif()
 
-if(Geant3_FOUND AND Geant4VMC_FOUND AND yaml-cpp_FOUND)
+if(Geant3_FOUND AND Geant4VMC_FOUND AND yaml-cpp_FOUND
+   AND TARGET FairRoot::FastSim)
   add_subdirectory(mcconfigurator)
 endif()