PR libstdc++/80446 cope with libc defining __has_builtin

	PR libstdc++/80446
	* include/std/type_traits (is_aggregate): Change __has_builtin checks.
	* libsupc++/new (launder): Likewise.

From-SVN: r246992

libstdc++-v3/ChangeLog

+2017-04-19  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/80446
+	* include/std/type_traits (is_aggregate): Change __has_builtin checks.
+	* libsupc++/new (launder): Likewise.
+
 2017-04-18  Jonathan Wakely  <jwakely@redhat.com>
 
 	* include/std/functional (default_searcher, __boyer_moore_array_base)

libstdc++-v3/include/std/type_traits

@@ -3062,14 +3062,16 @@ template <typename _From, typename _To>
 #endif
 #undef _GLIBCXX_NO_BUILTIN_HAS_UNIQ_OBJ_REP
 
-#ifdef __has_builtin
-# if !__has_builtin(__is_aggregate)
-// Try not to break non-GNU compilers that don't support the built-in:
-#  define _GLIBCXX_NO_BUILTIN_IS_AGGREGATE 1
+#if __GNUC__ >= 7
+# define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1
+#elif defined __has_builtin
+// For non-GNU compilers:
+# if __has_builtin(__is_aggregate)
+#  define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1
 # endif
 #endif
 
-#ifndef _GLIBCXX_NO_BUILTIN_IS_AGGREGATE
+#ifdef _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE
 #define __cpp_lib_is_aggregate 201703
   /// is_aggregate
   template<typename _Tp>
@@ -3080,7 +3082,7 @@ template <typename _From, typename _To>
   template<typename _Tp>
     inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
 #endif
-#undef _GLIBCXX_NO_BUILTIN_IS_AGGREGATE
+#undef _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE
 
 #endif // C++17
 

libstdc++-v3/libsupc++/new

@@ -177,14 +177,16 @@ inline void operator delete[](void*, void*) _GLIBCXX_USE_NOEXCEPT { }
 } // extern "C++"
 
 #if __cplusplus > 201402L
-#ifdef __has_builtin
-# if !__has_builtin(__builtin_launder)
-// Try not to break non-GNU compilers that don't support the built-in:
-#  define _GLIBCXX_NO_BUILTIN_LAUNDER 1
+#if __GNUC__ >= 7
+#  define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
+#elif defined __has_builtin
+// For non-GNU compilers:
+# if __has_builtin(__builtin_launder)
+#  define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
 # endif
 #endif
 
-#ifndef _GLIBCXX_NO_BUILTIN_LAUNDER
+#ifdef _GLIBCXX_HAVE_BUILTIN_LAUNDER
 namespace std
 {
 #define __cpp_lib_launder 201606
@@ -208,7 +210,7 @@ namespace std
   void launder(const volatile void*) = delete;
 }
 #endif // _GLIBCXX_NO_BUILTIN_LAUNDER
-#undef _GLIBCXX_NO_BUILTIN_LAUNDER
+#undef _GLIBCXX_HAVE_BUILTIN_LAUNDER
 #endif // C++17
 
 #pragma GCC visibility pop