Assume termios is available, remove support for termio and sgtty

This commit garbage collects the termio and sgtty support.

GDB's terminal handling code still has support for the old termio and
sgtty interfaces in addition to termios.  However, I think it's pretty
safe to assume that for a long, long time, Unix-like systems provide
termios.  GNU/Linux, Solaris, Cygwin, AIX, DJGPP, macOS and the BSDs
all have had termios.h for many years.  Looking around the web, I
found discussions about FreeBSD folks trying to get rid of old sgtty.h
a decade ago:

  https://lists.freebsd.org/pipermail/freebsd-hackers/2007-March/019983.html

So I think support for termio and sgtty in GDB is just dead code that
is never compiled anywhere and is just getting in the way.  For
example, serial_noflush_set_tty_state and the raw<->cooked concerns
mentioned in inflow.c only exist because of sgtty (see
hardwire_noflush_set_tty_state).

Regtested on GNU/Linux.

Confirmed that I can still build Solaris, DJGPP and AIX GDB and that
the resulting GDBs still include the termios.h-guarded code.
Confirmed mingw-w64 GDB still builds and skips the termios.h-guarded
code.

gdb/ChangeLog:
2017-11-06  Pedro Alves  <palves@redhat.com>

	* Makefile.in (SER_HARDWIRE): Update comment.
	(HFILES_NO_SRCDIR): Remove gdb_termios.h.
	* common/gdb_termios.h: Delete file.
	* common/job-control.c: Include termios.h and unistd.h instead of
	gdb_termios.h.
	(gdb_setpgid): Remove HAVE_TERMIOS || TIOCGPGRP preprocessor
	check.
	(have_job_control): Check HAVE_TERMIOS_H instead of HAVE_TERMIOS.
	Remove sgtty code.
	* configure.ac: No longer check for termio.h and sgtty.h.
	* configure: Regenerate.
	* inflow.c: Include termios.h instead of gdb_termios.h.  Replace
	PROCESS_GROUP_TYPE checks with HAVE_TERMIOS_H checks throughout.
	Replace PROCESS_GROUP_TYPE references with pid_t references
	throughout.
	(gdb_getpgrp): Delete.
	(set_initial_gdb_ttystate): Use tcgetpgrp instead of gdb_getpgrp.
	(child_terminal_inferior): Remove comment.  Remove sgtty code.
	(child_terminal_ours_1): Use tcgetpgrp directly instead of
	gdb_getpgrp.  Use serial_set_tty_state instead aof
	serial_noflush_set_tty_state.  Remove sgtty code.
	* inflow.h: Include unistd.h instead of gdb_termios.h.  Replace
	PROCESS_GROUP_TYPE check with HAVE_TERMIOS_H check.
	(inferior_process_group): Now returns pid_t.
	* ser-base.c (ser_base_noflush_set_tty_state): Delete.
	* ser-base.h (ser_base_noflush_set_tty_state): Delete.
	* ser-event.c (serial_event_ops): Update.
	* ser-go32.c (dos_noflush_set_tty_state): Delete.
	(dos_ops): Update.
	* ser-mingw.c (hardwire_ops, tty_ops, pipe_ops, tcp_ops): Update.
	* ser-pipe.c (pipe_ops): Update.
	* ser-tcp.c (tcp_ops): Update.
	* ser-unix.c: Include termios.h instead of gdb_termios.h.  Remove
	HAVE_TERMIOS checks.
	[HAVE_TERMIO] (struct hardwire_ttystate): Delete.
	[HAVE_SGTTY] (struct hardwire_ttystate): Delete.
	(get_tty_state, set_tty_state): Drop termio and sgtty code, and
	assume termios.
	(hardwire_noflush_set_tty_state): Delete.
	(hardwire_print_tty_state, hardwire_drain_output)
	(hardwire_flush_output, hardwire_flush_input)
	(hardwire_send_break, hardwire_raw, hardwire_setbaudrate)
	(hardwire_setstopbits, hardwire_setparity): Drop termio and sgtty
	code, and assume termios.
	(hardwire_ops): Update.
	(_initialize_ser_hardwire): Remove HAVE_TERMIOS check.
	* serial.c (serial_noflush_set_tty_state): Delete.
	* serial.h (serial_noflush_set_tty_state): Delete.
	(serial_ops::noflush_set_tty_state): Delete.

gdb/gdbserver/ChangeLog:
2017-11-06  Pedro Alves  <palves@redhat.com>

	* configure.ac: No longer check for termio.h and sgtty.h.
	* configure: Regenerate.
	* remote-utils.c: Include termios.h instead of gdb_termios.h.
	(remote_open): Check HAVE_TERMIOS_H instead of HAVE_TERMIOS.
	Remove termio and sgtty code.

2 files changed, 8 insertions, 93 deletions

diff --git a/gdb/common/gdb_termios.h b/gdb/common/gdb_termios.h
deleted file mode 100644
index 1d0544d74f3..00000000000
--- a/gdb/common/gdb_termios.h
+++ /dev/null
@@ -1,78 +0,0 @@
-/* Common terminal interface definitions for GDB and gdbserver.
-   Copyright (C) 1986-2017 Free Software Foundation, Inc.
-
-   This file is part of GDB.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
-
-#ifndef GDB_TERMIOS_H
-#define GDB_TERMIOS_H
-
-/* If we're using autoconf, it will define HAVE_TERMIOS_H,
-   HAVE_TERMIO_H and HAVE_SGTTY_H for us.  One day we can rewrite
-   ser-unix.c and inflow.c to inspect those names instead of
-   HAVE_TERMIOS, HAVE_TERMIO and the implicit HAVE_SGTTY (when neither
-   HAVE_TERMIOS or HAVE_TERMIO is set).  Until then, make sure that
-   nothing has already defined the one of the names, and do the right
-   thing.  */
-
-#if !defined (HAVE_TERMIOS) && !defined(HAVE_TERMIO) && !defined(HAVE_SGTTY)
-#if defined(HAVE_TERMIOS_H)
-#define HAVE_TERMIOS
-#else /* ! defined (HAVE_TERMIOS_H) */
-#if defined(HAVE_TERMIO_H)
-#define HAVE_TERMIO
-#else /* ! defined (HAVE_TERMIO_H) */
-#if defined(HAVE_SGTTY_H)
-#define HAVE_SGTTY
-#endif /* ! defined (HAVE_SGTTY_H) */
-#endif /* ! defined (HAVE_TERMIO_H) */
-#endif /* ! defined (HAVE_TERMIOS_H) */
-#endif /* !defined (HAVE_TERMIOS) && !defined (HAVE_TERMIO) &&
-	  !defined (HAVE_SGTTY) */
-
-#if defined(HAVE_TERMIOS)
-#include <termios.h>
-#endif
-
-#if !defined(_WIN32) && !defined (HAVE_TERMIOS)
-
-/* Define a common set of macros -- BSD based -- and redefine whatever
-   the system offers to make it look like that.  FIXME: serial.h and
-   ser-*.c deal with this in a much cleaner fashion; as soon as stuff
-   is converted to use them, can get rid of this crap.  */
-
-#ifdef HAVE_TERMIO
-
-#include <termio.h>
-
-#undef TIOCGETP
-#define TIOCGETP TCGETA
-#undef TIOCSETN
-#define TIOCSETN TCSETA
-#undef TIOCSETP
-#define TIOCSETP TCSETAF
-#define TERMINAL struct termio
-
-#else /* sgtty */
-
-#include <fcntl.h>
-#include <sgtty.h>
-#include <sys/ioctl.h>
-#define TERMINAL struct sgttyb
-
-#endif /* sgtty */
-#endif
-
-#endif /* ! GDB_TERMIOS_H */
diff --git a/gdb/common/job-control.c b/gdb/common/job-control.c
index d76bc57313e..78fc672f2c6 100644
--- a/gdb/common/job-control.c
+++ b/gdb/common/job-control.c
@@ -20,7 +20,10 @@
 
 #include "common-defs.h"
 #include "job-control.h"
-#include "gdb_termios.h"
+#ifdef HAVE_TERMIOS_H
+#include <termios.h>
+#endif
+#include <unistd.h>
 
 /* Nonzero if we have job control.  */
 int job_control;
@@ -41,7 +44,6 @@ gdb_setpgid ()
 
   if (job_control)
     {
-#if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
 #ifdef HAVE_SETPGID
       /* The call setpgid (0, 0) is supposed to work and mean the same
          thing as this, but on Ultrix 4.2A it fails with EPERM (and
@@ -56,7 +58,6 @@ gdb_setpgid ()
 #endif
 #endif /* HAVE_SETPGRP */
 #endif /* HAVE_SETPGID */
-#endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
     }
 
   return retval;
@@ -67,9 +68,9 @@ gdb_setpgid ()
 void
 have_job_control ()
 {
-  /* OK, figure out whether we have job control.  If neither termios nor
-     sgtty (i.e. termio or go32), leave job_control 0.  */
-#if defined (HAVE_TERMIOS)
+  /* OK, figure out whether we have job control.  If termios is not
+     available, leave job_control 0.  */
+#if defined (HAVE_TERMIOS_H)
   /* Do all systems with termios have the POSIX way of identifying job
      control?  I hope so.  */
 #ifdef _POSIX_JOB_CONTROL
@@ -81,13 +82,5 @@ have_job_control ()
   job_control = 0;		/* Have to assume the worst.  */
 #endif /* _SC_JOB_CONTROL */
 #endif /* _POSIX_JOB_CONTROL */
-#endif /* HAVE_TERMIOS */
-
-#ifdef HAVE_SGTTY
-#ifdef TIOCGPGRP
-  job_control = 1;
-#else
-  job_control = 0;
-#endif /* TIOCGPGRP */
-#endif /* sgtty */
+#endif /* HAVE_TERMIOS_H */
 }