Protect from comma operator overload

[François Dumont]

Hi

    While working on something else on libstdc++ I started having a 
test failing because of the missing comma overload protection in 
deque.tcc. So I looked for other similar places in the code and here is 
a patch to fix the places I found.

    Let me know if it is still time to commit.

François

diff --git a/libstdc++-v3/include/bits/deque.tcc b/libstdc++-v3/include/bits/deque.tcc
index fe96330..1337394 100644
--- a/libstdc++-v3/include/bits/deque.tcc
+++ b/libstdc++-v3/include/bits/deque.tcc
@@ -297,7 +297,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 		    std::input_iterator_tag)
       {
         iterator __cur = begin();
-        for (; __first != __last && __cur != end(); ++__cur, ++__first)
+        for (; __first != __last && __cur != end(); ++__cur, (void)++__first)
           *__cur = *__first;
         if (__first == __last)
           _M_erase_at_end(__cur);
diff --git a/libstdc++-v3/include/bits/list.tcc b/libstdc++-v3/include/bits/list.tcc
index 22538c9..e90d957 100644
--- a/libstdc++-v3/include/bits/list.tcc
+++ b/libstdc++-v3/include/bits/list.tcc
@@ -312,7 +312,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
         iterator __first1 = begin();
         iterator __last1 = end();
         for (; __first1 != __last1 && __first2 != __last2;
-	     ++__first1, ++__first2)
+	     ++__first1, (void)++__first2)
           *__first1 = *__first2;
         if (__first2 == __last2)
           erase(__first1, __last1);
diff --git a/libstdc++-v3/include/bits/stl_bvector.h b/libstdc++-v3/include/bits/stl_bvector.h
index 05e9ff2..4b52c17 100644
--- a/libstdc++-v3/include/bits/stl_bvector.h
+++ b/libstdc++-v3/include/bits/stl_bvector.h
@@ -1229,7 +1229,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 		      std::input_iterator_tag)
 	{
 	  iterator __cur = begin();
-	  for (; __first != __last && __cur != end(); ++__cur, ++__first)
+	  for (; __first != __last && __cur != end(); ++__cur, (void)++__first)
 	    *__cur = *__first;
 	  if (__first == __last)
 	    _M_erase_at_end(__cur);
diff --git a/libstdc++-v3/include/bits/vector.tcc b/libstdc++-v3/include/bits/vector.tcc
index 2516e35..f33da03 100644
--- a/libstdc++-v3/include/bits/vector.tcc
+++ b/libstdc++-v3/include/bits/vector.tcc
@@ -273,7 +273,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       {
 	pointer __cur(this->_M_impl._M_start);
 	for (; __first != __last && __cur != this->_M_impl._M_finish;
-	     ++__cur, ++__first)
+	     ++__cur, (void)++__first)
 	  *__cur = *__first;
 	if (__first == __last)
 	  _M_erase_at_end(__cur);