Assume at least POSIX.1-1988 for getpgrp, setpgid, setsid.

This removes code that has been obsolete since around 1990.
* admin/CPP-DEFINES (HAVE_SETPGID, HAVE_SETSID, SETPGRP_RELEASES_CTTY):
Remove; obsolete.
* configure.ac (setpgid, setsid): Assume their existence.
(AC_FUNC_GETPGRP, SETPGRP_RELEASES_CTTY): Remove; obsolete.
* src/callproc.c (Fcall_process):
* src/emacs.c (main):
* src/process.c (create_process):
* src/term.c (dissociate_if_controlling_tty):
Assume setsid exists.
* src/callproc.c (child_setup): Assume setpgid exists and behaves as
per POSIX.1-1988 or later.
* src/conf_post.h (setpgid) [!HAVE_SETPGID]: Remove.
* src/emacs.c (shut_down_emacs):
* src/sysdep.c (sys_suspend, init_foreground_group):
Assume getpgrp behaves as per POSIX.1-1998 or later.
* src/msdos.c (setpgrp): Remove.
(tcgetpgrp, setpgid, setsid): New functions.
* src/systty.h (EMACS_GETPGRP): Remove.  All callers now use getpgrp.
* src/term.c (no_controlling_tty): Remove; unused.
* src/w32proc.c (setpgrp): Remove.
(setsid, tcgetpgrp): New functions.

Fixes: debbugs:12800

1 files changed, 2 insertions, 33 deletions

diff --git a/src/term.c b/src/term.c
index ffc559469e6..578c701858f 100644
--- a/src/term.c
+++ b/src/term.c
@@ -133,10 +133,6 @@ enum no_color_bit
 
 static int max_frame_cols;
 
-/* Non-zero if we have dropped our controlling tty and therefore
-   should not open a frame on stdout. */
-static int no_controlling_tty;
-
 
 
 #ifdef HAVE_GPM
@@ -2918,36 +2914,9 @@ set_tty_hooks (struct terminal *terminal)
 static void
 dissociate_if_controlling_tty (int fd)
 {
-#ifndef DOS_NT
   pid_t pgid = tcgetpgrp (fd); /* If tcgetpgrp succeeds, fd is the ctty. */
-  if (pgid != -1)
-    {
-#if defined (USG5)
-      setpgrp ();
-      no_controlling_tty = 1;
-#elif defined (CYGWIN)
-      setsid ();
-      no_controlling_tty = 1;
-#else
-#ifdef TIOCNOTTY                /* Try BSD ioctls. */
-      sigset_t blocked;
-      sigemptyset (&blocked);
-      sigaddset (&blocked, SIGTTOU);
-      pthread_sigmask (SIG_BLOCK, &blocked, 0);
-      fd = emacs_open (DEV_TTY, O_RDWR, 0);
-      if (fd != -1 && ioctl (fd, TIOCNOTTY, 0) != -1)
-        {
-          no_controlling_tty = 1;
-        }
-      if (fd != -1)
-        emacs_close (fd);
-      pthread_sigmask (SIG_UNBLOCK, &blocked, 0);
-#else
-# error "Unknown system."
-#endif  /* ! TIOCNOTTY */
-#endif  /* ! USG */
-    }
-#endif  /* !DOS_NT */
+  if (0 <= pgid)
+    setsid ();
 }
 
 /* Create a termcap display on the tty device with the given name and