[gcc/devel/omp/gcc-9] Do not declare std::uses_allocator before C++11

[Tobias Burnus]

https://gcc.gnu.org/g:8fa40f2cc3616f39a94ff58d95c4c4421fd39e2a

commit 8fa40f2cc3616f39a94ff58d95c4c4421fd39e2a
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Oct 24 13:54:50 2019 +0100

    Do not declare std::uses_allocator before C++11
    
    Backport from mainline
    2019-10-22  Jonathan Wakely  <jwakely@redhat.com>
    
    	* include/bits/memoryfwd.h (uses_allocator): Do not declare for C++98.
    	* testsuite/17_intro/names.cc: Check uses_allocator in C++98.
    
    From-SVN: r277387

Diff:
---
 libstdc++-v3/ChangeLog                   | 6 ++++++
 libstdc++-v3/include/bits/memoryfwd.h    | 2 ++
 libstdc++-v3/testsuite/17_intro/names.cc | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 00cab77..fe6c649 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,6 +1,12 @@
 2019-10-24  Jonathan Wakely  <jwakely@redhat.com>
 
 	Backport from mainline
+	2019-10-22  Jonathan Wakely  <jwakely@redhat.com>
+
+	* include/bits/memoryfwd.h (uses_allocator): Do not declare for C++98.
+	* testsuite/17_intro/names.cc: Check uses_allocator in C++98.
+
+	Backport from mainline
 	2019-10-18  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/92143
diff --git a/libstdc++-v3/include/bits/memoryfwd.h b/libstdc++-v3/include/bits/memoryfwd.h
index 8b1664a..732ac80 100644
--- a/libstdc++-v3/include/bits/memoryfwd.h
+++ b/libstdc++-v3/include/bits/memoryfwd.h
@@ -66,9 +66,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<>
     class allocator<void>;
 
+#if __cplusplus >= 201103L
   /// Declare uses_allocator so it can be specialized in \<queue\> etc.
   template<typename, typename>
     struct uses_allocator;
+#endif
 
   /// @} group memory
 
diff --git a/libstdc++-v3/testsuite/17_intro/names.cc b/libstdc++-v3/testsuite/17_intro/names.cc
index 66c639f..a47d535 100644
--- a/libstdc++-v3/testsuite/17_intro/names.cc
+++ b/libstdc++-v3/testsuite/17_intro/names.cc
@@ -100,6 +100,10 @@
 
 #define tmp (
 
+#if __cplusplus < 201103L
+#define uses_allocator  (
+#endif
+
 #if __cplusplus < 201703L
 // <charconv> defines to_chars_result::ptr and to_chars_result::ec
 #define ec (