[Bug ada/66972] New: Ada.Directories doesn't recognize dangling symlinks

["pavel at zhukoff dot net" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66972

            Bug ID: 66972
           Summary: Ada.Directories doesn't recognize dangling symlinks
           Product: gcc
           Version: 5.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pavel at zhukoff dot net
  Target Milestone: ---

If symlink is broken Ada.Directories.Exists returns False (actually it's
because stat64 returns ENOENT in __gnat_stat). 

Easy to reproduce:
mkdir 'test' && cd 'test' && touch target && ln -s target link && rm target &&
cd - && ./del

where del is:
with Ada.Directories;
procedure del is 
begin
  Ada.Directories.Delete_Tree ("test");
end del; 


The problem is even worse if Ada.Direcotiries.Delete_Tree was called and
symlink's target was deleted before the symlink itself.
raised ADA.IO_EXCEPTIONS.USE_ERROR : directory tree rooted at ".uuid" could not
be deleted


The similar issue was reported already but closed with UNCONFIRMED:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63222