[PATCH] libstdc++: Explicitly pass -Wsystem-headers to tests that need it

[Patrick Palka]

Tested on x86_64-pc-linux-gnu, does thsi look OK for trunk and
perhaps 15/14?

-- >8 --

When running libstdc++ tests using an installed gcc (as opposed to
an in-tree gcc), warnings from within system headers are suppressed,
so tests that check for such warnings need to pass -Wsystem-headers
explicitly in order for them not to spuriously FAIL.

libstdc++-v3/ChangeLog:

        * testsuite/20_util/bind/dangling_ref.cc: Compile with
        -Wsystem-headers.
        * testsuite/20_util/ratio/operations/ops_overflow_neg.cc: Likewise.
        * testsuite/20_util/unique_ptr/lwg4148.cc: Likewise.
        * testsuite/29_atomics/atomic/operators/pointer_partial_void.cc:
        Likewise.
        * testsuite/30_threads/packaged_task/cons/dangling_ref.cc:
        Likewise.
---
 libstdc++-v3/testsuite/20_util/bind/dangling_ref.cc              | 1 +
 .../testsuite/20_util/ratio/operations/ops_overflow_neg.cc       | 1 +
 libstdc++-v3/testsuite/20_util/unique_ptr/lwg4148.cc             | 1 +
 .../29_atomics/atomic/operators/pointer_partial_void.cc          | 1 +
 .../testsuite/30_threads/packaged_task/cons/dangling_ref.cc      | 1 +
 5 files changed, 5 insertions(+)

diff --git a/libstdc++-v3/testsuite/20_util/bind/dangling_ref.cc 
b/libstdc++-v3/testsuite/20_util/bind/dangling_ref.cc
index 17e7b21c45cb..32af0a27b8fe 100644
--- a/libstdc++-v3/testsuite/20_util/bind/dangling_ref.cc
+++ b/libstdc++-v3/testsuite/20_util/bind/dangling_ref.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wsystem-headers" }
 #include <functional>
 
 int f();
diff --git 
a/libstdc++-v3/testsuite/20_util/ratio/operations/ops_overflow_neg.cc 
b/libstdc++-v3/testsuite/20_util/ratio/operations/ops_overflow_neg.cc
index 5eff8e31f82a..cdc46f4a7ea2 100644
--- a/libstdc++-v3/testsuite/20_util/ratio/operations/ops_overflow_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/ratio/operations/ops_overflow_neg.cc
@@ -1,5 +1,6 @@
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
+// { dg-additional-options "-Wsystem-headers" }
 
 // 2008-07-03 Chris Fairles <chris.fair...@gmail.com>
 
diff --git a/libstdc++-v3/testsuite/20_util/unique_ptr/lwg4148.cc 
b/libstdc++-v3/testsuite/20_util/unique_ptr/lwg4148.cc
index c70d7a60631b..f5697e4e4021 100644
--- a/libstdc++-v3/testsuite/20_util/unique_ptr/lwg4148.cc
+++ b/libstdc++-v3/testsuite/20_util/unique_ptr/lwg4148.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wsystem-headers" }
 
 // LWG 4148. unique_ptr::operator* should not allow dangling references
 
diff --git 
a/libstdc++-v3/testsuite/29_atomics/atomic/operators/pointer_partial_void.cc 
b/libstdc++-v3/testsuite/29_atomics/atomic/operators/pointer_partial_void.cc
index e959418a1c3c..1e2f71e9c628 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic/operators/pointer_partial_void.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/operators/pointer_partial_void.cc
@@ -1,6 +1,7 @@
 // { dg-do run { target { c++11_only || c++14_only } } }
 // { dg-require-atomic-builtins "" }
 // { dg-require-effective-target hosted }
+// { dg-additional-options "-Wsystem-headers" }
 
 // Copyright (C) 2012-2025 Free Software Foundation, Inc.
 //
diff --git 
a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/dangling_ref.cc 
b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/dangling_ref.cc
index 8cc3f78da9f0..30e05b0391a1 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/dangling_ref.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/dangling_ref.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wsystem-headers" }
 #include <future>
 
 // C++20 [futures.task.members]
-- 
2.51.0.268.ga483264b01