From 8e9f5d11b164af9defc71a3010637d1926ef4018 Mon Sep 17 00:00:00 2001
From: jmcarcell <jmcarcell@users.noreply.github.com>
Date: Fri, 15 Sep 2023 10:36:26 +0200
Subject: [PATCH] Check if the CLHEP target exists before creating it

---
 cmake/DD4hepBuild.cmake | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cmake/DD4hepBuild.cmake b/cmake/DD4hepBuild.cmake
index ab12d75a7..add54c83a 100644
--- a/cmake/DD4hepBuild.cmake
+++ b/cmake/DD4hepBuild.cmake
@@ -826,7 +826,9 @@ MACRO(DD4HEP_SETUP_GEANT4_TARGETS)
 
     if(Geant4_builtin_clhep_FOUND)
       dd4hep_debug("Using Geant4 internal CLHEP")
-      ADD_LIBRARY(CLHEP::CLHEP INTERFACE IMPORTED GLOBAL)
+      IF(NOT TARGET CLHEP::CLHEP)
+        ADD_LIBRARY(CLHEP::CLHEP INTERFACE IMPORTED GLOBAL)
+      ENDIF()
       SET_TARGET_PROPERTIES(CLHEP::CLHEP
         PROPERTIES
         INTERFACE_INCLUDE_DIRECTORIES "${Geant4_INCLUDE_DIRS}"