[gcc(refs/vendors/ibm/heads/perf)] libstdc++: ranges::iter_move should perform ADL-only lookup (LWG 3247)

[Jiu Fu Guo]

https://gcc.gnu.org/g:59aa9e577eb2b182374f5421828687c93b81ad3d

commit 59aa9e577eb2b182374f5421828687c93b81ad3d
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Feb 19 16:43:07 2020 +0000

    libstdc++: ranges::iter_move should perform ADL-only lookup (LWG 3247)
    
            * include/bits/iterator_concepts.h (iter_move): Add declaration to
            prevent unqualified lookup finding a suitable declaration (LWG 3247).

Diff:
---
 libstdc++-v3/ChangeLog                        | 3 +++
 libstdc++-v3/include/bits/iterator_concepts.h | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 067cf8343f6..689bee8c2a9 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,8 @@
 2020-02-19  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/iterator_concepts.h (iter_move): Add declaration to
+	prevent unqualified lookup finding a suitable declaration (LWG 3247).
+
 	* include/std/memory_resource (polymorphic_allocator::allocate)
 	(polymorphic_allocator::allocate_object): Change type of exception to
 	bad_array_new_length (LWG 3237).
diff --git a/libstdc++-v3/include/bits/iterator_concepts.h b/libstdc++-v3/include/bits/iterator_concepts.h
index 792b3262106..08e622259b4 100644
--- a/libstdc++-v3/include/bits/iterator_concepts.h
+++ b/libstdc++-v3/include/bits/iterator_concepts.h
@@ -79,6 +79,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   {
     namespace __cust_imove
     {
+      void iter_move();
+
       template<typename _Tp>
 	concept __adl_imove
 	  = (std::__detail::__class_or_enum<remove_reference_t<_Tp>>)