diff --git a/Source/cmDefinitions.cxx b/Source/cmDefinitions.cxx
index 6502163791..5515f35516 100644
--- a/Source/cmDefinitions.cxx
+++ b/Source/cmDefinitions.cxx
@@ -15,7 +15,8 @@
 cmDefinitions::Def cmDefinitions::NoDef;
 
 //----------------------------------------------------------------------------
-cmDefinitions::cmDefinitions(cmDefinitions* parent): Up(parent)
+cmDefinitions::cmDefinitions(cmDefinitions* parent)
+  : Up(parent)
 {
 }
 
@@ -35,7 +36,7 @@ cmDefinitions::GetInternal(const std::string& key) const
     {
     return i->second;
     }
-  else if(cmDefinitions* up = this->Up)
+  if(cmDefinitions* up = this->Up)
     {
     // Query the parent scope.
     return up->GetInternal(key);
diff --git a/Source/cmDefinitions.h b/Source/cmDefinitions.h
index ebe6fa5f3f..5209a8b201 100644
--- a/Source/cmDefinitions.h
+++ b/Source/cmDefinitions.h
@@ -13,6 +13,9 @@
 #define cmDefinitions_h
 
 #include "cmStandardIncludes.h"
+#if defined(CMAKE_BUILD_WITH_CMAKE)
+#include "cmsys/hash_map.hxx"
+#endif
 
 /** \class cmDefinitions
  * \brief Store a scope of variable definitions for CMake language.
@@ -71,7 +74,11 @@ private:
   cmDefinitions* Up;
 
   // Local definitions, set or unset.
+#if defined(CMAKE_BUILD_WITH_CMAKE)
+  typedef cmsys::hash_map<std::string, Def> MapType;
+#else
   typedef std::map<std::string, Def> MapType;
+#endif
   MapType Map;
 
   // Internal query and update methods.