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, 16 deletions

diff --git a/src/process.c b/src/process.c
index 3c0e53f7784..16600f94ce4 100644
--- a/src/process.c
+++ b/src/process.c
@@ -1739,7 +1739,6 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
       /* Make the pty be the controlling terminal of the process.  */
 #ifdef HAVE_PTYS
       /* First, disconnect its current controlling terminal.  */
-#ifdef HAVE_SETSID
       /* We tried doing setsid only if pty_flag, but it caused
          process_set_signal to fail on SGI when using a pipe.  */
       setsid ();
@@ -1752,12 +1751,6 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
           ioctl (xforkin, TIOCSCTTY, 0);
 #endif
         }
-#else /* not HAVE_SETSID */
-      /* It's very important to call setpgid here and no time
-         afterwards.  Otherwise, we lose our controlling tty which
-         is set when we open the pty. */
-      setpgid (0, 0);
-#endif /* not HAVE_SETSID */
 #if defined (LDISC1)
       if (pty_flag && xforkin >= 0)
         {
@@ -1790,22 +1783,15 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
               ioctl (j, TIOCNOTTY, 0);
               emacs_close (j);
             }
-#ifndef USG
-          /* In order to get a controlling terminal on some versions
-             of BSD, it is necessary to put the process in pgrp 0
-             before it opens the terminal.  */
-          setpgid (0, 0);
-#endif
         }
 #endif /* TIOCNOTTY */
 
 #if !defined (DONT_REOPEN_PTY)
 /*** There is a suggestion that this ought to be a
-     conditional on TIOCSPGRP,
-     or !(defined (HAVE_SETSID) && defined (TIOCSCTTY)).
+     conditional on TIOCSPGRP, or !defined TIOCSCTTY.
      Trying the latter gave the wrong results on Debian GNU/Linux 1.1;
      that system does seem to need this code, even though
-     both HAVE_SETSID and TIOCSCTTY are defined.  */
+     both TIOCSCTTY is defined.  */
         /* Now close the pty (if we had it open) and reopen it.
            This makes the pty the controlling terminal of the subprocess.  */
       if (pty_flag)