Fix use of throw(...) spec with GCC in C++17

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290845 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/new b/include/new
index 6b432f2..442e113 100644
--- a/include/new
+++ b/include/new
@@ -162,7 +162,7 @@
 
 }  // std
 
-#if !__has_feature(cxx_noexcept)
+#if defined(_LIBCPP_CXX03_LANG)
 #define _THROW_BAD_ALLOC throw(std::bad_alloc)
 #else
 #define _THROW_BAD_ALLOC