[gcc r15-7857] libstdc++: Avoid '-Wunused-parameter' for 'nofollow' in static member function 'static std::filesyst

[Thomas Schwinge]

https://gcc.gnu.org/g:5029c4bd330849fd6513b290d38bce853b320c5b

commit r15-7857-g5029c4bd330849fd6513b290d38bce853b320c5b
Author: Thomas Schwinge <tschwinge@baylibre.com>
Date:   Wed Feb 19 20:15:30 2025 +0100

    libstdc++: Avoid '-Wunused-parameter' for 'nofollow' in static member function 'static std::filesystem::__gnu_posix::DIR* std::filesystem::_Dir_base::openat(const _At_path&, bool)'
    
    In a newlib configuration:
    
        In file included from ../../../../../source-gcc/libstdc++-v3/src/c++17/fs_dir.cc:37,
                         from ../../../../../source-gcc/libstdc++-v3/src/c++17/cow-fs_dir.cc:26:
        ../../../../../source-gcc/libstdc++-v3/src/c++17/../filesystem/dir-common.h: In static member function ‘static std::filesystem::__gnu_posix::DIR* std::filesystem::_Dir_base::openat(const _At_path&, bool)’:
        ../../../../../source-gcc/libstdc++-v3/src/c++17/../filesystem/dir-common.h:210:36: error: unused parameter ‘nofollow’ [-Werror=unused-parameter]
          210 |   openat(const _At_path& atp, bool nofollow)
              |                               ~~~~~^~~~~~~~
    
            libstdc++-v3/
            * src/filesystem/dir-common.h (openat): Tag 'nofollow' as
            '[[maybe_unused]]'.

Diff:
---
 libstdc++-v3/src/filesystem/dir-common.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/src/filesystem/dir-common.h b/libstdc++-v3/src/filesystem/dir-common.h
index 5ff621c3380a..c7d4bc4e6ed7 100644
--- a/libstdc++-v3/src/filesystem/dir-common.h
+++ b/libstdc++-v3/src/filesystem/dir-common.h
@@ -207,7 +207,7 @@ struct _Dir_base
   }
 
   static posix::DIR*
-  openat(const _At_path& atp, bool nofollow)
+  openat(const _At_path& atp, [[maybe_unused]] bool nofollow)
   {
 #if _GLIBCXX_HAVE_FDOPENDIR && defined O_RDONLY && defined O_DIRECTORY \
     && ! _GLIBCXX_FILESYSTEM_IS_WINDOWS