Fix various GCC mis-configurations for newer versions.

This patch goes through and enables C++11 and C++14 features for newer GCC's.
The main changes are:

1. Turn on variable templates. (Uses __cpp_variable_templates)
2. Assert atomic<Tp> is trivially copyable (Uses _GNUC_VER >= 501).
3. Turn on trailing return support for GCC. (Uses _GNUC_VER >= 404)
4. XFAIL void_t test for GCC 5.1 and 5.2. Fixed in GCC 6.

llvm-svn: 255585

1 files changed, 4 insertions, 5 deletions

diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
index 5deeeff110d..ccec65fec39 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
@@ -11,11 +11,11 @@
 
 // void_t
 
-#include <type_traits>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// XFAIL: gcc-5.1 gcc-5.2
 
-#if _LIBCPP_STD_VER <= 14
-int main () {}
-#else
+#include <type_traits>
 
 template <class T>
 void test1()
@@ -66,4 +66,3 @@ int main()
 
     static_assert( std::is_same<void, std::void_t<int, double const &, Class, volatile int[], void>>::value, "");
 }
-#endif