Merged revisions 61152,61185 via svnmerge from

https://svn.boost.org/svn/boost/trunk

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  r61152 | jhunold | 2010-04-09 11:04:51 +0200 (Fr, 09 Apr 2010) | 2 lines
  
  Silence gcc warnings when using UnaryFunction with reference parameters.
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  r61185 | jhunold | 2010-04-10 19:50:26 +0200 (Sa, 10 Apr 2010) | 2 lines
  
  Dummy-Constructor only for gcc > 4.
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[SVN r61205]

include/boost/concept_check.hpp

@@ -330,7 +330,16 @@ namespace boost
       {
           f(arg);
       }
-      
+
+#if (BOOST_WORKAROUND(__GNUC__, BOOST_TESTED_AT(4) \
+                      && BOOST_WORKAROUND(__GNUC__, > 3)))
+      // Declare a dummy construktor to make gcc happy.
+      // It seems the compiler can not generate a sensible constructor when this is instantiated with a refence type.
+      // (warning: non-static reference "const double& boost::UnaryFunction<YourClassHere>::arg"
+      // in class without a constructor [-Wuninitialized])
+      UnaryFunction();
+#endif
+
       Func f;
       Arg arg;
   };