cmState: Initialize top level source directories immediately.

Don't leave this as cmMakefile responsibility.

Source/cmMakefile.cxx

@@ -119,10 +119,6 @@ cmMakefile::cmMakefile(cmGlobalGenerator* globalGenerator,
   this->AddSourceGroup("Object Files", "\\.(lo|o|obj)$");
 #endif
 
-  this->StateSnapshot.SetDefinition("CMAKE_SOURCE_DIR",
-                      this->GetCMakeInstance()->GetHomeDirectory());
-  this->StateSnapshot.SetDefinition("CMAKE_BINARY_DIR",
-                      this->GetCMakeInstance()->GetHomeOutputDirectory());
   {
   const char* dir = this->StateSnapshot.GetDirectory().GetCurrentSource();
   if (dir)

Source/cmState.cxx

@@ -306,11 +306,21 @@ cmState::Snapshot cmState::Reset()
   pos->PolicyScope = this->PolicyStack.Root();
   assert(pos->Policies.IsValid());
   assert(pos->PolicyRoot.IsValid());
+
+  {
+  std::string srcDir =
+      cmDefinitions::Get("CMAKE_SOURCE_DIR", pos->Vars, pos->Root);
+  std::string binDir =
+      cmDefinitions::Get("CMAKE_BINARY_DIR", pos->Vars, pos->Root);
   this->VarTree.Clear();
   pos->Vars = this->VarTree.Extend(this->VarTree.Root());
   pos->Parent = this->VarTree.Root();
   pos->Root = this->VarTree.Root();
 
+  pos->Vars->Set("CMAKE_SOURCE_DIR", srcDir.c_str());
+  pos->Vars->Set("CMAKE_BINARY_DIR", binDir.c_str());
+  }
+
   this->DefineProperty
     ("RULE_LAUNCH_COMPILE", cmProperty::DIRECTORY,
      "", "", true);
@@ -838,6 +848,7 @@ cmState::CreateBuildsystemDirectorySnapshot(Snapshot originSnapshot,
   cmState::Snapshot snapshot = cmState::Snapshot(this, pos);
   originSnapshot.Position->BuildSystemDirectory->Children.push_back(snapshot);
   snapshot.InitializeFromParent();
+  snapshot.SetDirectoryDefinitions();
   return snapshot;
 }
 
@@ -1318,6 +1329,14 @@ void InitializeContentFromParent(T& parentContent,
   contentEndPosition = thisContent.size();
 }
 
+void cmState::Snapshot::SetDirectoryDefinitions()
+{
+  this->SetDefinition("CMAKE_SOURCE_DIR",
+                      this->State->GetSourceDirectory());
+  this->SetDefinition("CMAKE_BINARY_DIR",
+                      this->State->GetBinaryDirectory());
+}
+
 void cmState::Snapshot::InitializeFromParent()
 {
   PositionType parent = this->Position->DirectoryParent;

Source/cmState.h

@@ -96,6 +96,8 @@ public:
                       const cmState::Snapshot& rhs) const;
     };
 
+    void SetDirectoryDefinitions();
+
   private:
     friend bool operator==(const cmState::Snapshot& lhs,
                            const cmState::Snapshot& rhs);

Source/cmake.cxx

@@ -980,6 +980,10 @@ cmGlobalGenerator* cmake::CreateGlobalGenerator(const std::string& gname)
 void cmake::SetHomeDirectory(const std::string& dir)
 {
   this->State->SetSourceDirectory(dir);
+  if (this->CurrentSnapshot.IsValid())
+    {
+    this->CurrentSnapshot.SetDefinition("CMAKE_SOURCE_DIR", dir);
+    }
 }
 
 const char* cmake::GetHomeDirectory() const
@@ -990,6 +994,10 @@ const char* cmake::GetHomeDirectory() const
 void cmake::SetHomeOutputDirectory(const std::string& dir)
 {
   this->State->SetBinaryDirectory(dir);
+  if (this->CurrentSnapshot.IsValid())
+    {
+    this->CurrentSnapshot.SetDefinition("CMAKE_BINARY_DIR", dir);
+    }
 }
 
 const char* cmake::GetHomeOutputDirectory() const