[gcc r16-7665] libstdc++: Replace check for exceptions in mdspan/at.cc.

[Tomasz Kaminski]

https://gcc.gnu.org/g:7ff0e39d0d5a81a09cb9e126b3f511464f972ee9

commit r16-7665-g7ff0e39d0d5a81a09cb9e126b3f511464f972ee9
Author: Tomasz Kamiński <tkaminsk@redhat.com>
Date:   Tue Feb 24 18:20:53 2026 +0100

    libstdc++: Replace check for exceptions in mdspan/at.cc.
    
    Uses __cpp_lib_constexpr_exceptions, that better expresses
    the intent.
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/23_containers/mdspan/at.cc: Updated guard.

Diff:
---
 libstdc++-v3/testsuite/23_containers/mdspan/at.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/at.cc b/libstdc++-v3/testsuite/23_containers/mdspan/at.cc
index d9edce464add..c5a12d12cccb 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/at.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/at.cc
@@ -89,7 +89,7 @@ template<typename Int, bool ValidForPacks, bool ValidForArrays>
       }
     };
 
-#if !_GLIBCXX_USE_CXX11_ABI
+#if !__cpp_lib_constexpr_exceptions
     if consteval {
       return true;
     }