Remove NO_SOCK_SIGIO references.

* src/m/template.h (NO_SOCK_SIGIO): Remove, no longer used.

* nextstep/DEV-NOTES: Remove out-of-date information.

nextstep/DEV-NOTES

@@ -64,13 +64,8 @@ functions are:
 
 Currently ctrl-g is not detected in as many circumstances as other emacsen.
 It is not certain whether this is due to the means of event loop integration,
-or errors of omission in the NS code.  One area for exploration is the
-NO_SOCK_SIGIO define.  When it is defined, ctrl-g seems to be picked up more
-often, but there are some annoying side effects.  Currently it is left off by
-default, unless the --enable-cocoa-experimental-ctrl-g option is passed to
-configure [option removed Feb 2009].  (Has no effect under GNUstep.)
-This is an area for improvement.  Also, see the article here and its
-containing thread:
+or errors of omission in the NS code.  This is an area for improvement.
+Also, see the article here and its containing thread:
 
 http://article.gmane.org/gmane.emacs.devel/92021/match=handling%5fsignal
 

src/ChangeLog

 2010-06-03  Glenn Morris  <rgm@gnu.org>
 
+	* m/template.h (NO_SOCK_SIGIO): Remove, no longer used.
+
 	* m/hp800.h (alloca) [__NetBSD__ && __GNUC__]: No need to define it,
 	now that AH_BOTTOM does it.
 

src/m/template.h

@@ -58,17 +58,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    code will not be sharable; but that's better than failing completely.  */
 #define NO_REMAP
 
-/* Some really obscure 4.2-based systems (like Sequent DYNIX)
-   do not support asynchronous I/O (using SIGIO) on sockets,
-   even though it works fine on tty's.  If you have one of
-   these systems, define the following, and then use it in
-   config.h (or elsewhere) to decide when (not) to use SIGIO.
-
-   You'd think this would go in an operating-system description file,
-   but since it only occurs on some, but not all, BSD systems, the
-   reasonable place to select for it is in the machine description file.  */
-#define NO_SOCK_SIGIO
-
 /* After adding support for a new machine, modify the large case
    statement in configure.in to recognize reasonable
    configuration names, and add a description of the system to