[PATCH] AIX xfail for_overwrite.cc libstdc++ testcase

[David Edelsohn]

The 20_util/unique_ptr/creation/for_overwrite.cc test relies on
operator new, which requires special features on AIX.  This patch
disables the testcase.

Thanks, David

--- a/libstdc++-v3/testsuite/20_util/unique_ptr/creation/for_overwrite.cc
+++ b/libstdc++-v3/testsuite/20_util/unique_ptr/creation/for_overwrite.cc
@@ -1,5 +1,6 @@
 // { dg-options "-std=gnu++20" }
 // { dg-do run { target c++2a } }
+// { dg-xfail-run-if "AIX operator new" { powerpc-ibm-aix* } }

 // Copyright (C) 2020 Free Software Foundation, Inc.
 //