Remove macro MIN_PTY_KERNEL_VERSION, only used in one place

* src/process.c (init_process_emacs): Replace MIN_PTY_KERNEL_VERSION.
* src/s/darwin.h (MIN_PTY_KERNEL_VERSION): Remove single-use macro.

src/ChangeLog

+2012-07-13  Glenn Morris  <rgm@gnu.org>
+
+	* process.c (init_process_emacs): Replace MIN_PTY_KERNEL_VERSION.
+	* s/darwin.h (MIN_PTY_KERNEL_VERSION): Remove single-use macro.
+
 2012-07-12  Glenn Morris  <rgm@gnu.org>
 	* s/darwin.h (SYSTEM_PURESIZE_EXTRA): Move to configure.

src/process.c

@@ -7398,8 +7398,7 @@ init_process_emacs (void)
     char const *release = (STRINGP (Voperating_system_release)
 			   ? SSDATA (Voperating_system_release)
 			   : 0);
-    if (!release || !release[0] || (release[0] < MIN_PTY_KERNEL_VERSION
-				    && release[1] == '.')) {
+    if (!release || !release[0] || (release[0] < '7' && release[1] == '.')) {
       Vprocess_connection_type = Qnil;
     }
   }

src/s/darwin.h

@@ -30,10 +30,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    distinguish OS X from pure Darwin.  */
 #define DARWIN_OS
 
-/* PTYs only work correctly on Darwin 7 or higher.  So make the default
-   for process-connection-type dependent on the kernel version.  */
-#define MIN_PTY_KERNEL_VERSION '7'
-
 /* Definitions for how to compile & link.  */
 #ifdef emacs
 #define malloc unexec_malloc