libstdc++: Remove redundant -std=gnu++17 option from strings tests

GCC defaults to -std=gnu++17 now anyway, and using it explicitly in the
dg-options directive prevents running these tests with different modes
such as -std=c++17 or -std=gnu++20.

libstdc++-v3/ChangeLog:

	* testsuite/21_strings/basic_string/79162.cc: Remove
	-std=gnu++17 from dg-options directive.
	* testsuite/21_strings/basic_string/cons/char/7.cc: Likewise.
	* testsuite/21_strings/basic_string/cons/char/79162.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/char/86138.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/char/9.cc: Likewise.
	* testsuite/21_strings/basic_string/cons/char/deduction.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/char/moveable2_c++17.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/wchar_t/7.cc: Likewise.
	* testsuite/21_strings/basic_string/cons/wchar_t/79162.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/wchar_t/86138.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/wchar_t/9.cc: Likewise.
	* testsuite/21_strings/basic_string/cons/wchar_t/deduction.cc:
	Likewise.
	* testsuite/21_strings/basic_string/cons/wchar_t/moveable2_c++17.cc:
	Likewise.
	* testsuite/21_strings/basic_string/hash/hash.cc: Likewise.
	* testsuite/21_strings/basic_string/lwg2758.cc: Likewise.
	* testsuite/21_strings/basic_string/lwg2946.cc: Likewise.
	* testsuite/21_strings/basic_string/modifiers/append/char/4.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/append/wchar_t/4.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/assign/char/4.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/assign/wchar_t/4.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/insert/char/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/insert/wchar_t/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/replace/char/7.cc:
	Likewise.
	* testsuite/21_strings/basic_string/modifiers/replace/wchar_t/7.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/compare/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/compare/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/data/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/data/char/86169.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/data/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/find/char/5.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operations/find/wchar_t/5.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operators/char/5.cc:
	Likewise.
	* testsuite/21_strings/basic_string/operators/wchar_t/5.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/capacity/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/capacity/empty_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/char/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/char/nonnull.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/wchar_t/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/back_constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/constexpr.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/empty.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/front_back.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/front_back_constexpr.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/front_constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/back_constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/empty.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/front_back.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/include.cc: Likewise.
	* testsuite/21_strings/basic_string_view/inserters/94051.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/char/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/pod/10081-out.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/inserters/wchar_t/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/literals/types-char8_t.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/literals/types.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/literals/values-char8_t.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/literals/values.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/modifiers/remove_prefix/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/modifiers/remove_prefix/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/modifiers/remove_suffix/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/modifiers/remove_suffix/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/modifiers/swap/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/modifiers/swap/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/char/13650.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/char/70483.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/char/nonnull.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/wchar_t/13650.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/compare/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/copy/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/copy/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/copy/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/copy/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/data/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/data/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/char/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/char/4.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/char/nonnull.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/wchar_t/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/find/wchar_t/4.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/char/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/char/nonnull.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/rfind/wchar_t/3.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/string_conversion/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/substr/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/substr/char/83511.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/substr/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operations/substr/wchar_t/83511.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operators/char/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operators/char/89446.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operators/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operators/wchar_t/89446.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/range_access/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/range_access/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/explicit_instantiation/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/explicit_instantiation/char/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/explicit_instantiation/char16_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/explicit_instantiation/char32_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/explicit_instantiation/char8_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/explicit_instantiation/wchar_t/1.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/traits_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/requirements/typedefs.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/typedefs.cc: Likewise.
	* testsuite/21_strings/basic_string_view/types/1.cc: Likewise.
	* testsuite/21_strings/char_traits/requirements/char/99181.cc:
	Likewise.
	* testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc:

1 files changed, 1 insertions, 1 deletions

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc
index bd32d88482a..fdcabd7363d 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc
@@ -15,7 +15,7 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
-// { dg-options "-std=gnu++17 -D_GLIBCXX_ASSERTIONS" }
+// { dg-options "-D_GLIBCXX_ASSERTIONS" }
 // { dg-do compile { target c++17 xfail *-*-* } }
 
 #include <string_view>