Add the ability to exclude dir-locals from subdirs. (Bug#8100)

* lisp/files.el (dir-locals-collect-variables):
Add the ability to exclude subdirectories.

* doc/emacs/custom.texi (Directory Variables):
Give an example of excluding subdirectories.

* doc/lispref/variables.texi (Directory Local Variables):
Mention `(subdirs . nil)' alist element.

* etc/NEWS: Mention this addition.

* lisp/dired-x.el (dired-omit-here-always): Add `(subdirs . nil)' to locals.

2 files changed, 11 insertions, 2 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index c8925715f74..1a980f14f3d 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,8 @@
+2011-03-01  Glenn Morris  <rgm@gnu.org>
+
+        * variables.texi (Directory Local Variables):
+        Mention `(subdirs . nil)' alist element.
+
 2011-02-28  Glenn Morris  <rgm@gnu.org>
 
         * variables.texi (Directory Local Variables): Mention the optional
diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi
index c6af304416c..a68b2b6dd4e 100644
--- a/doc/lispref/variables.texi
+++ b/doc/lispref/variables.texi
@@ -1718,7 +1718,8 @@ directory-local variables.  The name of the file is
 The MS-DOS version of Emacs uses @file{_dir-locals.el} instead, due to
 limitations of the DOS filesystems.
 }.  A file by that name in a directory causes Emacs to apply its
-settings to any file in that directory or any of its subdirectories.
+settings to any file in that directory or any of its subdirectories
+(optionally, you can exclude subdirectories; see below).
 If some of the subdirectories have their own @file{.dir-locals.el}
 files, Emacs uses the settings from the deepest file it finds starting
 from the file's directory and moving up the directory tree.  The file
@@ -1749,7 +1750,10 @@ file's buffer turns on a mode that is derived from @var{major-mode},
 then the all the variables in the associated @var{alist} are applied;
 @var{alist} should be of the form @code{(@var{name} . @var{value})}.
 A special value @code{nil} for @var{major-mode} means the settings are
-applicable to any mode.
+applicable to any mode.  In @var{alist}, you can use a special
+@var{name}: @code{subdirs}.  If the associated value is
+@code{nil}, the alist is only applied to files in the relevant
+directory, not to those in any subdirectories.
 
 With the second form of @var{variables}, if @var{directory} is the
 initial substring of the file's directory, then @var{list} is applied