[gcc r12-9910] libstdc++: Fix linker errors for directory iterator comparisons

[gcc r12-9910] libstdc++: Fix linker errors for directory iterator comparisons

[Jonathan Wakely]

https://gcc.gnu.org/g:222a58dc8f390f72e90d09dd9bea31c67e87bcc0

commit r12-9910-g222a58dc8f390f72e90d09dd9bea31c67e87bcc0
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Oct 3 17:41:14 2023 +0100

    libstdc++: Fix linker errors for directory iterator comparisons
    
    These new comparison operators for std::default_sentinel_t require some
    new symbol exports, which were added with r13-5662-gdb8d6fc572ec31 for
    trunk, but that isn't suitable for the gcc-12 branch.
    
    Define them as specified in the standard instead, which doesn't require
    any new symbols.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/fs_dir.h (directory_iterator::operator==):
            Define without using a non-exported shared_ptr symbol.
            (recursive_directory_iterator::operator==): Likewise.

Diff:
---
 libstdc++-v3/include/bits/fs_dir.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/bits/fs_dir.h b/libstdc++-v3/include/bits/fs_dir.h
index bec2b7674ef..84e8e8984e8 100644
--- a/libstdc++-v3/include/bits/fs_dir.h
+++ b/libstdc++-v3/include/bits/fs_dir.h
@@ -433,7 +433,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 3719. Directory iterators should be usable with default sentinel
       bool operator==(default_sentinel_t) const noexcept
-      { return !_M_dir; }
+      { return *this == directory_iterator(); }
 #endif
 
 #if __cpp_impl_three_way_comparison < 201907L
@@ -541,7 +541,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 3719. Directory iterators should be usable with default sentinel
       bool operator==(default_sentinel_t) const noexcept
-      { return !_M_dirs; }
+      { return *this == recursive_directory_iterator(); }
 #endif
 
 #if __cpp_impl_three_way_comparison < 201907L