A patch for Emacs 24.5 to add a `--nofork' command line option, which turns out to be kinda useless but hey it's neat

emacs-nofork.patch

--- src/emacs-dist.c	2015-07-17 08:33:53.065388047 -0400
+++ src/emacs.c	2015-07-17 09:54:39.085327207 -0400
@@ -1012,6 +1012,13 @@
 #ifndef DOS_NT
       pid_t f;
 
+      int no_fork = 0;
+
+      if (argmatch(argv, argc, "-nofork", "--nofork", 5, NULL, &skip_args)) {
+	fprintf(stderr, "Daemon won't background itself.\n");
+	no_fork = 1;
+      }
+
       /* Start as a daemon: fork a new child process which will run the
 	 rest of the initialization code, then exit.
 
@@ -1045,10 +1052,12 @@
 Emacs might crash when run in daemon mode and the X11 connection is unexpectedly lost.\n\
 Using an Emacs configured with --with-x-toolkit=lucid does not have this problem.\n");
 #endif /* USE_GTK */
-      f = fork ();
+      if (!no_fork) {
+	f = fork ();
+      }
 #else /* DAEMON_MUST_EXEC */
-      if (!dname_arg || !strchr (dname_arg, '\n'))
-	  f = fork ();  /* in orig */
+      if (!no_fork && (!dname_arg || !strchr (dname_arg, '\n')))
+	f = fork ();  /* in orig */
       else
 	  f = 0;  /* in exec'd */
 #endif /* !DAEMON_MUST_EXEC */
@@ -1058,7 +1067,9 @@
 	  char buf[1];
 
 	  /* Close unused writing end of the pipe.  */
-	  emacs_close (daemon_pipe[1]);
+	  if (!no_fork) {
+	    emacs_close (daemon_pipe[1]);
+	  }
 
 	  /* Just wait for the child to close its end of the pipe.  */
 	  do
@@ -1078,7 +1089,9 @@
 	      exit (1);
 	    }
 
-	  emacs_close (daemon_pipe[0]);
+	  if (!no_fork) {
+	    emacs_close (daemon_pipe[0]);
+	  }
 	  exit (0);
 	}
       if (f < 0)
@@ -1106,9 +1119,11 @@
 
             argv[skip_args] = fdStr;
 
-	    fcntl (daemon_pipe[0], F_SETFD, 0);
-	    fcntl (daemon_pipe[1], F_SETFD, 0);
-            execvp (argv[0], argv);
+	    if (!no_fork) {
+	      fcntl (daemon_pipe[0], F_SETFD, 0);
+	      fcntl (daemon_pipe[1], F_SETFD, 0);
+	      execvp (argv[0], argv);
+	    }
 	    emacs_perror (argv[0]);
 	    exit (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
           }
@@ -1130,10 +1145,13 @@
 
       if (dname_arg)
        	daemon_name = xstrdup (dname_arg);
-      /* Close unused reading end of the pipe.  */
-      emacs_close (daemon_pipe[0]);
+      if (!no_fork) {
+	/* Close unused reading end of the pipe.  */
+	emacs_close (daemon_pipe[0]);
+	/* Set new session (not parent's) */
+	setsid ();
+      }
 
-      setsid ();
 #else /* DOS_NT */
       fprintf (stderr, "This platform does not support the -daemon flag.\n");
       exit (1);
@@ -1667,6 +1685,7 @@
   { "-batch", "--batch", 100, 0 },
   { "-script", "--script", 100, 1 },
   { "-daemon", "--daemon", 99, 0 },
+  { "-nofork", "--nofork", 98, 0 },
   { "-help", "--help", 90, 0 },
   { "-nl", "--no-loadup", 70, 0 },
   { "-nsl", "--no-site-lisp", 65, 0 },