Unordered: Fix complex type for gcc's standard library. Fixes #6139.

I haven't had any confirmation, but I assume this fixes the problem.


[SVN r75909]

include/boost/detail/container_fwd.hpp

@@ -42,6 +42,10 @@
         || defined(_GLIBCXX_PARALLEL) \
         || defined(_GLIBCXX_PROFILE)
 #      define BOOST_DETAIL_NO_CONTAINER_FWD
+#    else
+#      if defined(__GLIBCXX__) && __GLIBCXX__ >= 20040530
+#        define BOOST_CONTAINER_FWD_COMPLEX_STRUCT
+#      endif
 #    endif
 #  elif defined(__STL_CONFIG_H)
      // generic SGI STL
@@ -63,8 +67,6 @@
 #  elif (defined(_YVALS) && !defined(__IBMCPP__)) || defined(_CPPLIB_VER)
      // Dinkumware Library (this has to appear after any possible replacement
      // libraries)
-     //
-     // Works fine.
 #  else
 #    define BOOST_DETAIL_NO_CONTAINER_FWD
 #  endif
@@ -117,11 +119,11 @@ namespace std
     template <class charT> struct char_traits;
 #endif
 
-    #if BOOST_CLANG
-        template <class T> struct complex;
-    #else
-        template <class T> class complex;
-    #endif
+#if defined(BOOST_CONTAINER_FWD_COMPLEX_STRUCT)
+    template <class T> struct complex;
+#else
+    template <class T> class complex;
+#endif
 
 #if !defined(BOOST_CONTAINER_FWD_BAD_DEQUE)
     template <class T, class Allocator> class deque;

test/container_fwd/Jamfile

@@ -11,6 +11,7 @@ project detail/test/container_fwd
         <toolset>intel:<warnings>on
         <toolset>gcc:<cxxflags>"-pedantic -Wstrict-aliasing -fstrict-aliasing -Wextra -Wsign-promo -Wunused-parameter -Wconversion"
         <toolset>darwin:<cxxflags>"-pedantic -Wstrict-aliasing -fstrict-aliasing -Wextra -Wsign-promo -Wunused-parameter -Wconversion"
+        <toolset>clang:<cxxflags>"-pedantic -Wextra -Wmismatched-tags"
         <warnings-as-errors>on
   ;