[gcc r16-7047] aarch64: fix `mangle_5.C` test

[Karl Meakin]

https://gcc.gnu.org/g:939cebe693c52e76a584b886e70417f48327f98a

commit r16-7047-g939cebe693c52e76a584b886e70417f48327f98a
Author: Karl Meakin <karl.meakin@arm.com>
Date:   Thu Dec 11 16:24:51 2025 +0000

    aarch64: fix `mangle_5.C` test
    
    The `volatile` type qualifier is deprecated on function parameters and
    return types since C++ 20. This caused extra warning to be emmitted, so
    the test failed. Fix it by suppressing the warning.
    
    gcc/testsuite/ChangeLog:
    
            * g++.target/aarch64/sve/acle/general-c++/mangle_5.C: Fix test.

Diff:
---
 gcc/testsuite/g++.target/aarch64/sve/acle/general-c++/mangle_5.C | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gcc/testsuite/g++.target/aarch64/sve/acle/general-c++/mangle_5.C b/gcc/testsuite/g++.target/aarch64/sve/acle/general-c++/mangle_5.C
index 1504cc12f41b..73254844e346 100644
--- a/gcc/testsuite/g++.target/aarch64/sve/acle/general-c++/mangle_5.C
+++ b/gcc/testsuite/g++.target/aarch64/sve/acle/general-c++/mangle_5.C
@@ -1,3 +1,7 @@
+// { dg-options "-Wno-volatile" }
+// Disable warning about volatile qualifier on function arguments as they are
+// deprecated in C++20.
+
 typedef const __SVInt8_t foo;
 typedef volatile foo bar;