Create gdb_termios.h (and cleanup gdb/{,gdbserver/}terminal.h)

As requested, I'm sending this as a separate patch because it is ready
to be included as-is.

The idea here is that both gdb/terminal.h and gdb/gdbserver/terminal.h
share the same code, which is responsible for setting a bunch of
defines on based on the presence of termios.h and a few other headers.
This simple patch just moves this common code to common/gdb_termios.h
and makes the necessary adjustments on both GDB and gdbserver so that
they can use this new header.  It also implements the some header
checks on common/common.m4.

As a bonus, gdb/gdbserver/terminal.h can be removed because it's now
empty.

Built on x86_64, no regressions found.

gdb/ChangeLog:
2017-04-12  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (HFILES_NO_SRCDIR): Add "common/gdb_termios.h".
	* common/common.m4: Check headers 'termios.h', 'termio.h' and
	'sgtty.h'.
	* common/gdb_termios.h: New file, with parts of "terminal.h".
	* inflow.c: Include "gdb_termios.h".
	* ser-unix.c: Include "gdb_termios.h".
	* terminal.h: Move terminal-related defines to
	"common/gdb_termios.h".

gdb/gdbserver/ChangeLog:
2017-04-12  Sergio Durigan Junior  <sergiodj@redhat.com>

	* remote-utils.c: Include "gdb_termios.h" instead of
	"terminal.h".
	* terminal.h: Delete file.

2 files changed, 80 insertions, 1 deletions

diff --git a/gdb/common/common.m4 b/gdb/common/common.m4
index e21e6e5..45726ab 100644
--- a/gdb/common/common.m4
+++ b/gdb/common/common.m4
@@ -28,7 +28,8 @@ AC_DEFUN([GDB_AC_COMMON], [
   AC_CHECK_HEADERS(linux/perf_event.h locale.h memory.h signal.h dnl
 		   sys/resource.h sys/socket.h sys/syscall.h dnl
 		   sys/un.h sys/wait.h dnl
-		   thread_db.h wait.h)
+		   thread_db.h wait.h dnl
+		   termios.h termio.h sgtty.h)
 
   AC_CHECK_FUNCS([fdwalk getrlimit pipe pipe2 socketpair sigaction])
 
diff --git a/gdb/common/gdb_termios.h b/gdb/common/gdb_termios.h
new file mode 100644
index 0000000..1d0544d
--- /dev/null
+++ b/gdb/common/gdb_termios.h
@@ -0,0 +1,78 @@
+/* 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 */