diff --git a/Source/cmGlobalUnixMakefileGenerator3.h b/Source/cmGlobalUnixMakefileGenerator3.h
index bce1b37451..5cfe26fb20 100644
--- a/Source/cmGlobalUnixMakefileGenerator3.h
+++ b/Source/cmGlobalUnixMakefileGenerator3.h
@@ -176,7 +176,6 @@ protected:
   // in the rule to satisfy the make program.
   std::string EmptyRuleHackCommand;
 
-  std::map<cmStdString, int > TargetSourceFileCount;
   bool ForceVerboseMakefiles;
 };