[gcc r10-10215] libstdc++: Ensure test is compiled as C++17

[Jonathan Wakely]

https://gcc.gnu.org/g:5a25cb046dde7e734a066d9f335c6d29b5afb71f

commit r10-10215-g5a25cb046dde7e734a066d9f335c6d29b5afb71f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Oct 12 21:36:17 2021 +0100

    libstdc++: Ensure test is compiled as C++17
    
    This test was backported from trunk where the default is -std=gnu++17
    but for the gcc-10 branch we need to add that explicitly.
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc:
            Use -std=gnu++17 option.

Diff:
---
 .../21_strings/basic_string_view/requirements/trivially_copyable.cc      | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc
index 3f2589c61d8..bf04587b413 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc
@@ -1,3 +1,4 @@
+// { dg-options "-std=gnu++17" }
 // { dg-do compile { target c++17 } }
 
 // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2251r1.pdf