cmMakefile: Extract InitializeVarScope method.

Source/cmMakefile.cxx

@@ -55,6 +55,11 @@ public:
     this->VarStack.push_back(cmDefinitions());
   }
 
+  void InitializeVarScope()
+  {
+    this->PushDefinitions();
+  }
+
   void InitializeDefinitions(cmMakefile* parent)
   {
     this->VarStack.back() =
@@ -141,7 +146,7 @@ cmMakefile::cmMakefile(cmLocalGenerator* localGenerator)
     LocalGenerator(localGenerator),
     StateSnapshot(localGenerator->GetStateSnapshot())
 {
-  this->Internal->PushDefinitions();
+  this->Internal->InitializeVarScope();
   this->Internal->IsSourceFileTryCompile = false;
 
   // Initialize these first since AddDefaultDefinitions calls AddDefinition