Fix a compilation failure with g++-3.3.

* src/misc/hash.hh (identity_hash): New function.
* src/tgba/tgbaexplicit.hh (tgba_explicit_number): Use
identity_hash<int> instead of std::tr1::hash<int> that does not
exist with g++-3.3.

ChangeLog

+2011-01-12  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Fix a compilation failure with g++-3.3.
+
+	* src/misc/hash.hh (identity_hash): New function.
+	* src/tgba/tgbaexplicit.hh (tgba_explicit_number): Use
+	identity_hash<int> instead of std::tr1::hash<int> that does not
+	exist with g++-3.3.
+
 2011-01-07  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	Fix usage of minimize_obligation in the CGI script.

src/misc/hash.hh

-// Copyright (C) 2008 Laboratoire de Recherche et Développement
+// Copyright (C) 2008, 2011 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 // Copyright (C) 2003, 2004, 2005 Laboratoire d'Informatique de
 // Paris 6 (LIP6), département Systèmes Répartis Coopératifs (SRC),
@@ -86,7 +86,7 @@ namespace spot
 #  if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4
   typedef std::tr1::hash<std::string> string_hash;
 #  else  // GCC < 4.3
-  struct string_hash :
+  struct string_hash:
     public Sgi::hash<const char*>,
     public std::unary_function<const std::string&, size_t>
   {
@@ -99,6 +99,18 @@ namespace spot
   };
   /// @}
 #  endif
+
+  /// \brief A hash function that returns identity
+  /// \ingroup hash_funcs
+  template<typename T>
+  struct identity_hash:
+    public std::unary_function<const T&, size_t>
+  {
+    size_t operator()(const T& s) const
+    {
+      return s;
+    }
+  };
 }
 
 #endif // SPOT_MISC_HASH_HH

src/tgba/tgbaexplicit.hh

@@ -360,11 +360,11 @@ namespace spot
 
 #ifndef SWIG
   class tgba_explicit_number:
-    public tgba_explicit_labelled<int, std::tr1::hash<int> >
+    public tgba_explicit_labelled<int, identity_hash<int> >
   {
   public:
     tgba_explicit_number(bdd_dict* dict):
-      tgba_explicit_labelled<int, std::tr1::hash<int> >(dict)
+      tgba_explicit_labelled<int, identity_hash<int> >(dict)
     {};
     virtual ~tgba_explicit_number();
     virtual state* add_default_init();