* fix nullptr with gcc 3.4

merge to release

[[Imported from SVN: r5875]]

dune/common/nullptr.hh

@@ -26,6 +26,18 @@ private:
 
 typedef dune_nullptr_t nullptr_t;
 
+template<class T>
+bool operator == (T* t, dune_nullptr_t)
+{
+  return (t == static_cast<T*>(nullptr));
+}
+
+template<class T>
+bool operator == (dune_nullptr_t, T* t)
+{
+  return (t == static_cast<T*>(nullptr));
+}
+
 #endif // HAVE_NULLPTR
 
 #endif // DUNE_NULLPTR_HH

dune/common/test/nullptr-test.cc

@@ -17,6 +17,7 @@ void basic_tests()
   int n2 = 0;            // n2 is zero
   if( ch == 0 ) ;        // evaluates to true
   if( ch == nullptr ) ;  // evaluates to true
+  if( nullptr == ch ) ;  // evaluates to true
   if( ch ) ;             // evaluates to false
   if( n2 == 0 ) ;        // evaluates to true
   ch = ch2;