[v3] Minor fixes for algorithm/iterator

[Paolo Carlini]

Hi,

This one fixes three minor problems of mine and Phil's recent commits. Tested
i686-pc-linux-gnu. Approved by Phil Edwards.

Cheers,
Paolo.

///////////

2001-12-31  Paolo Carlini  <pcarlini@unitus.it>

        * include/backward/algo.h:  Add two more using declarations.
        * include/backward/iterator.h:  Include <ext/iterator>,
        add using declaration.
        * include/ext/algorithm:  Add #pragma GCC system_header.

diff -urN libstdc++-v3-orig/include/backward/algo.h
libstdc++-v3/include/backward/algo.h
--- libstdc++-v3-orig/include/backward/algo.h Mon Dec 31 10:10:39 2001
+++ libstdc++-v3/include/backward/algo.h Mon Dec 31 17:48:05 2001
@@ -135,7 +135,9 @@
 using __gnu_cxx::random_sample;
 using __gnu_cxx::random_sample_n;
 using __gnu_cxx::is_sorted;
-using __gnu_cxx::is_heap;
+using __gnu_cxx::is_heap;
+using __gnu_cxx::count;   // Extension returning void
+using __gnu_cxx::count_if;   // Extension returning void

 #endif /* _CPP_BACKWARD_ALGO_H */

diff -urN libstdc++-v3-orig/include/backward/iterator.h
libstdc++-v3/include/backward/iterator.h
--- libstdc++-v3-orig/include/backward/iterator.h Wed Dec 19 22:57:40 2001
+++ libstdc++-v3/include/backward/iterator.h Mon Dec 31 17:46:25 2001
@@ -36,6 +36,8 @@
 #include <bits/stl_construct.h>
 #include <bits/stl_raw_storage_iter.h>

+#include <ext/iterator> // For 3-parameter distance extension
+
 // Names from stl_iterator.h
 using std::input_iterator_tag;
 using std::output_iterator_tag;
@@ -112,7 +114,8 @@
   value_type(const _Iter& __i)
   { return static_cast<typename iterator_traits<_Iter>::value_type*>(0); }

-using std::distance;
+using std::distance;
+using __gnu_cxx::distance; // 3-parameter extension
 using std::advance;

 using std::insert_iterator;

diff -urN libstdc++-v3-orig/include/ext/algorithm
libstdc++-v3/include/ext/algorithm
--- libstdc++-v3-orig/include/ext/algorithm Fri Dec 28 19:46:53 2001
+++ libstdc++-v3/include/ext/algorithm Mon Dec 31 17:52:42 2001
@@ -56,6 +56,7 @@
 #ifndef _EXT_ALGORITHM
 #define _EXT_ALGORITHM

+#pragma GCC system_header
 #include <bits/std_algorithm.h>

 namespace __gnu_cxx