[gcc r17-2628] libstdc++: std::variant test should be C++17 and up

[Jonathan Wakely]

https://gcc.gnu.org/g:ab087de8fd6990dae01995a537ff4772d6282989

commit r17-2628-gab087de8fd6990dae01995a537ff4772d6282989
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jul 22 19:22:44 2026 +0100

    libstdc++: std::variant test should be C++17 and up
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/20_util/variant/lwg3990.cc: Change et to c++17.

Diff:
---
 libstdc++-v3/testsuite/20_util/variant/lwg3990.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/20_util/variant/lwg3990.cc b/libstdc++-v3/testsuite/20_util/variant/lwg3990.cc
index eab23c71a5d4..21231d6b5baa 100644
--- a/libstdc++-v3/testsuite/20_util/variant/lwg3990.cc
+++ b/libstdc++-v3/testsuite/20_util/variant/lwg3990.cc
@@ -1,4 +1,4 @@
-// { dg-do compile { target c++11 } }
+// { dg-do compile { target c++17 } }
 
 // LWG 3990. Program-defined specializations of std::tuple and std::variant
 // can't be properly supported