Attempt to fix aligned allocation configuration under clang-cl

When we're using clang-cl and Microsoft's runtime implementation,
we don't provide align_val_t or aligned new/delete ourselves.

This patch updates the _LIBCPP_HAS_NO_ALIGNED_ALLOCATION macro
to reflect this.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@343441 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/new b/include/new
index 8d72ba5..7c3076c 100644
--- a/include/new
+++ b/include/new
@@ -171,6 +171,10 @@
 enum align_val_t { __zero = 0, __max = (size_t)-1 };
 #endif
 #endif
+#elif !defined(__cpp_aligned_new)
+// We're defering to Microsoft's STL to provide aligned new et al. We don't
+// have it unless the language feature test macro is defined.
+#define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
 #endif
 
 }  // std