Backport: * lisp/files.el: Remove support for extra .dir-locals file

(dir-locals-file-2, dir-locals--all-files): Remove.
(dir-locals-collect-variables, dir-locals-file, dir-locals-find-file)
(dir-locals-read-from-file, hack-dir-local-variables): Revert changes.

* lisp/files-x.el (modify-dir-local-variable): Revert changes.

* lisp/help-fns.el (describe-variable): Revert changes.

* doc/emacs/custom.texi (Directory Variables): Revert changes.

* etc/NEWS: Revert changes.

1 files changed, 1 insertions, 5 deletions

diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
index 7be660c85d1..c1093353757 100644
--- a/doc/emacs/custom.texi
+++ b/doc/emacs/custom.texi
@@ -1298,11 +1298,7 @@ accomplished with @dfn{directory-local variables}.
 named @file{.dir-locals.el}@footnote{ On MS-DOS, the name of this file
 should be @file{_dir-locals.el}, due to limitations of the DOS
 filesystems.  If the filesystem is limited to 8+3 file names, the name
-of the file will be truncated by the OS to @file{_dir-loc.el}.
-}@footnote{ You can also use @file{.dir-locals-2.el}, which
-is loaded in addition.  This is useful when @file{.dir-locals.el} is
-under version control in a shared repository and can't be used for
-personal customizations.  } in a
+of the file will be truncated by the OS to @file{_dir-loc.el}.  } in a
 directory.  Whenever Emacs visits any file in that directory or any of
 its subdirectories, it will apply the directory-local variables
 specified in @file{.dir-locals.el}, as though they had been defined as