From 95f3b09de3183d9de61dd8cbd39fd7015a3a36a1 Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Wed, 5 Oct 2016 10:11:30 +0200
Subject: [PATCH] Use the same test as in <CGAL/config.h>

---
 .../config/support/CGAL_test_cpp_version.cpp        | 13 ++++++++++---
 Installation/include/CGAL/config.h                  |  1 +
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Installation/config/support/CGAL_test_cpp_version.cpp b/Installation/config/support/CGAL_test_cpp_version.cpp
index a6c812a7f9e..08c507a9883 100644
--- a/Installation/config/support/CGAL_test_cpp_version.cpp
+++ b/Installation/config/support/CGAL_test_cpp_version.cpp
@@ -1,5 +1,10 @@
 #include <iostream>
 
+// This file displays the value of `__cplusplus` on `stderr`, and then
+// return 0 if and only if C++ `thread_local` feature can be used.
+// The tests are the same as for the definition of
+// `CGAL_CAN_USE_CXX11_THREAD_LOCAL` in `<CGAL/config.h>`.
+
 #ifndef __has_feature
   #define __has_feature(x) 0  // Compatibility with non-clang compilers.
 #endif
@@ -10,10 +15,12 @@ int main() {
   return 1;
 #else
   std::cout << __cplusplus;
-#  if __has_feature(cxx_thread_local) || __cplusplus >= 201103L
+#endif
+
+#if __has_feature(cxx_thread_local) || \
+    ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L )
   return 0;
-#  else
+#else
   return 1;
-#  endif
 #endif
 }
diff --git a/Installation/include/CGAL/config.h b/Installation/include/CGAL/config.h
index 0e960f5ad7b..862c92372b6 100644
--- a/Installation/include/CGAL/config.h
+++ b/Installation/include/CGAL/config.h
@@ -473,6 +473,7 @@ using std::max;
 #if __has_feature(cxx_thread_local) || \
     ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L ) || \
     ( _MSC_VER >= 1900 )
+// see also Installation/config/support/CGAL_test_cpp_version.cpp
 #define CGAL_CAN_USE_CXX11_THREAD_LOCAL
 #endif