Index: emacsclient.c
===================================================================
RCS file: /sources/emacs/emacs/lib-src/emacsclient.c,v
retrieving revision 1.121
diff -U 4 -r1.121 emacsclient.c
--- emacsclient.c	26 Jan 2008 21:27:38 -0000	1.121
+++ emacsclient.c	4 Feb 2008 14:50:22 -0000
@@ -171,8 +171,9 @@
 #endif
   { "server-file",	required_argument, NULL, 'f' },
 #ifndef WINDOWSNT
   { "display",	required_argument, NULL, 'd' },
+  { "this-display", no_argument, NULL, 'D'},
 #endif
   { 0, 0, 0, 0 }
 };
 
@@ -479,24 +480,15 @@
      char **argv;
 {
   alternate_editor = egetenv ("ALTERNATE_EDITOR");
 
-  /* We used to set `display' to $DISPLAY by default, but this changed the
-     default behavior and is sometimes inconvenient.  So instead of forcing
-     users to say "--display ''" when they want to use Emacs's existing tty
-     or display connection, we force them to use "--display $DISPLAY" if
-     they want Emacs to connect to their current display.  */
-#if 0
-  display = egetenv ("DISPLAY");
-#endif
-
   while (1)
     {
       int opt = getopt_long (argc, argv,
 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
-			     "VHnea:s:f:d:tc",
+			     "VHnea:s:f:d:Dtc",
 #else
-			     "VHnea:f:d:tc",
+			     "VHnea:f:d:Dtc",
 #endif
 			     longopts, 0);
 
       if (opt == EOF)
@@ -530,8 +522,11 @@
 #if 1 /* !defined WINDOWS */
 	case 'd':
 	  display = optarg;
 	  break;
+        case 'D':
+	  display = egetenv ("DISPLAY");
+	  break;
 #endif
 
 	case 'n':
 	  nowait = 1;
@@ -612,9 +607,11 @@
 			use the current Emacs frame\n\
 -e, --eval    		Evaluate the FILE arguments as ELisp expressions\n\
 -n, --no-wait		Don't wait for the server to return\n"
 #ifndef WINDOWSNT
-"-d, --display=DISPLAY	Visit the file in the given display\n"
+"-d, --display=DISPLAY	Visit the file in the given X11 display\n"
+"-D, --this-display	Visit the file in current X11 display\n\
+			(found in environment variable $DISPLAY)\n"
 #endif
 #ifndef NO_SOCKETS_IN_FILE_SYSTEM
 "-s, --socket-name=FILENAME\n\
 			Set filename of the UNIX socket for communication\n"