[gcc r11-11038] libstdc++: Fix std::filesystem build failure for Windows

[Jonathan Wakely]

https://gcc.gnu.org/g:fee2458097e6167521676785f5b7c47331636e2e

commit r11-11038-gfee2458097e6167521676785f5b7c47331636e2e
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Feb 4 23:54:17 2022 +0000

    libstdc++: Fix std::filesystem build failure for Windows
    
    The std::filesystem code needs to use posix::DIR not ::DIR, as that is
    an alias for _WDIR on Windows.
    
    libstdc++-v3/ChangeLog:
    
            * src/filesystem/dir-common.h (_Dir_base::openat): Change return
            type to use portable posix::DIR alias.
    
    (cherry picked from commit 6e3419529d4e3284172f9965b4993b9f184f34d2)

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 33892c49bf2..bc734881782 100644
--- a/libstdc++-v3/src/filesystem/dir-common.h
+++ b/libstdc++-v3/src/filesystem/dir-common.h
@@ -173,7 +173,7 @@ struct _Dir_base
     return true;
   }
 
-  static ::DIR*
+  static posix::DIR*
   openat(int fd, const posix::char_type* pathname, bool nofollow)
   {
 #if _GLIBCXX_HAVE_FDOPENDIR && defined O_RDONLY && defined O_DIRECTORY \