rename local _C2 identifiers in stl map header files

2020-01-09  Olivier Hainque  <hainque@adacore.com>

	* doc/xml/manual/appendix_contributing.xml: Document _C2
	as a reserved identifier, by VxWorks.
	* include/bits/stl_map.h: Rename _C2 template typenames	as _Cmp2.
	* include/bits/stl_multimap.h: Likewise.

From-SVN: r280076

libstdc++-v3/ChangeLog

+2020-01-09  Olivier Hainque  <hainque@adacore.com>
+
+	* doc/xml/manual/appendix_contributing.xml: Document _C2
+	as a reserved identifier, by VxWorks.
+	* include/bits/stl_map.h: Rename _C2 template typenames	as _Cmp2.
+	* include/bits/stl_multimap.h: Likewise.
+
 2020-01-09  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/ext/extptr_allocator.h (_ExtPtr_allocator::operator==)

libstdc++-v3/doc/xml/manual/appendix_contributing.xml

@@ -463,6 +463,9 @@ indicate a place that may require attention for multi-thread safety.
       _res_ext
       __tg_*
 
+      VxWorks adds:
+      _C2
+
       For GCC:
 
       [Note that this list is out of date. It applies to the old

libstdc++-v3/include/bits/stl_map.h

@@ -637,30 +637,30 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       template<typename, typename>
 	friend class std::_Rb_tree_merge_helper;
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(map<_Key, _Tp, _C2, _Alloc>& __source)
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>& __source)
 	{
-	  using _Merge_helper = _Rb_tree_merge_helper<map, _C2>;
+	  using _Merge_helper = _Rb_tree_merge_helper<map, _Cmp2>;
 	  _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
 	}
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(map<_Key, _Tp, _C2, _Alloc>&& __source)
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>&& __source)
 	{ merge(__source); }
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(multimap<_Key, _Tp, _C2, _Alloc>& __source)
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>& __source)
 	{
-	  using _Merge_helper = _Rb_tree_merge_helper<map, _C2>;
+	  using _Merge_helper = _Rb_tree_merge_helper<map, _Cmp2>;
 	  _M_t._M_merge_unique(_Merge_helper::_S_get_tree(__source));
 	}
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(multimap<_Key, _Tp, _C2, _Alloc>&& __source)
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>&& __source)
 	{ merge(__source); }
 #endif // C++17
 

libstdc++-v3/include/bits/stl_multimap.h

@@ -653,30 +653,30 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       template<typename, typename>
 	friend class std::_Rb_tree_merge_helper;
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(multimap<_Key, _Tp, _C2, _Alloc>& __source)
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>& __source)
 	{
-	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _C2>;
+	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _Cmp2>;
 	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
 	}
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(multimap<_Key, _Tp, _C2, _Alloc>&& __source)
+	merge(multimap<_Key, _Tp, _Cmp2, _Alloc>&& __source)
 	{ merge(__source); }
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(map<_Key, _Tp, _C2, _Alloc>& __source)
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>& __source)
 	{
-	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _C2>;
+	  using _Merge_helper = _Rb_tree_merge_helper<multimap, _Cmp2>;
 	  _M_t._M_merge_equal(_Merge_helper::_S_get_tree(__source));
 	}
 
-      template<typename _C2>
+      template<typename _Cmp2>
 	void
-	merge(map<_Key, _Tp, _C2, _Alloc>&& __source)
+	merge(map<_Key, _Tp, _Cmp2, _Alloc>&& __source)
 	{ merge(__source); }
 #endif // C++17