diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 17bde4189..20c56ba6d 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -1906,6 +1906,11 @@ const char* cmMakefile::GetCurrentBinaryDirectory() const
   return this->StateSnapshot.GetDirectory().GetCurrentBinary();
 }
 
+void cmMakefile::AddGeneratorTarget(cmTarget* t, cmGeneratorTarget* gt)
+{
+  this->GeneratorTargets[t] = gt;
+}
+
 //----------------------------------------------------------------------------
 void cmMakefile::AddIncludeDirectories(const std::vector<std::string> &incs,
                                        bool before)
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 4fa58227e..1e5c301e9 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -417,10 +417,7 @@ public:
     {
       this->GeneratorTargets = targets;
     }
-  void AddGeneratorTarget(cmTarget* t, cmGeneratorTarget* gt)
-  {
-    this->GeneratorTargets[t] = gt;
-  }
+  void AddGeneratorTarget(cmTarget* t, cmGeneratorTarget* gt);
 
   cmTarget* FindTarget(const std::string& name,
                        bool excludeAliases = false) const;