[committed] Limit header synopsis test to normal namespace

[François Dumont via Gcc-patches]

Committed as trivial.

    libstdc++: Limit <stacktrace> synopsis test to normal namespace

    libstdc++-v3/ChangeLog

            * testsuite/19_diagnostics/stacktrace/synopsis.cc: Add
            { dg-require-normal-namespace "" }.

François

diff --git a/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc b/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc
index ece5d526fb9..21c94f34a13 100644
--- a/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc
+++ b/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc
@@ -1,6 +1,7 @@
 // { dg-options "-std=gnu++23" }
 // { dg-do compile { target c++23 } }
 // { dg-require-effective-target stacktrace }
+// { dg-require-normal-namespace "" }
 
 #include <stacktrace>