Move gdbserver to top level

This patch moves gdbserver to the top level.

This patch is as close to a pure move as possible -- gdbserver still
builds its own variant of gnulib and gdbsupport.  Changing this will
be done in a separate patch.

[v2] Note that, per Simon's review comment, this patch changes the
tree so that gdbserver is not built for or1k or score.  This makes
sense, because there is apparently not actually a gdbserver port here.

[v3] This version of the patch also splits out some configury into a
new file, gdbserver/configure.host, so that the top-level configure
script can simply rely on it in order to decide whether gdbserver
should be built.

[v4] This version adds documentation and removes some unnecessary
top-level dependencies.

[v5] Update docs to mention "make all-gdbserver" and change how
top-level configure decides whether to build gdbserver, switching to a
single, shared script.

Tested by the buildbot.

ChangeLog
2020-02-07  Tom Tromey  <tom@tromey.com>
	    Pedro Alves  <palves@redhat.com>

	* src-release.sh (GDB_SUPPORT_DIRS): Add gdbserver.
	* gdbserver: New directory, moved from gdb/gdbserver.
	* configure.ac (host_tools): Add gdbserver.
	Only build gdbserver on certain systems.
	* Makefile.in, configure: Rebuild.
	* Makefile.def (host_modules, dependencies): Add gdbserver.
	* MAINTAINERS: Add gdbserver.

gdb/ChangeLog
2020-02-07  Tom Tromey  <tom@tromey.com>

	* README: Update gdbserver documentation.
	* gdbserver: Move to top level.
	* configure.tgt (build_gdbserver): Remove.
	* configure.ac: Remove --enable-gdbserver.
	* configure: Rebuild.
	* Makefile.in (distclean): Don't mention gdbserver.

Change-Id: I826b7565b54604711dc7a11edea0499cd51ff39e

1 files changed, 68 insertions, 0 deletions

diff --git a/gdbserver/notif.h b/gdbserver/notif.h
new file mode 100644
index 0000000..c5d48c0
--- /dev/null
+++ b/gdbserver/notif.h
@@ -0,0 +1,68 @@
+/* Notification to GDB.
+   Copyright (C) 1989-2020 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 GDBSERVER_NOTIF_H
+#define GDBSERVER_NOTIF_H
+
+#include "target.h"
+#include <list>
+
+/* Structure holding information related to a single event.  We
+   keep a queue of these to push to GDB.  It can be extended if
+   the event of given notification contains more information.  */
+
+struct notif_event
+{
+  virtual ~notif_event ()
+  {
+  }
+
+  /* No payload needed.  */
+};
+
+/* A type notification to GDB.  An object of 'struct notif_server'
+   represents a type of notification.  */
+
+typedef struct notif_server
+{
+  /* The name of ack packet, for example, 'vStopped'.  */
+  const char *ack_name;
+
+  /* The notification packet, for example, '%Stop'.  Note that '%' is
+     not in 'notif_name'.  */
+  const char *notif_name;
+
+  /* A queue of events to GDB.  A new notif_event can be enque'ed
+     into QUEUE at any appropriate time, and the notif_reply is
+     deque'ed only when the ack from GDB arrives.  */
+  std::list<notif_event *> queue;
+
+  /* Write event EVENT to OWN_BUF.  */
+  void (*write) (struct notif_event *event, char *own_buf);
+} *notif_server_p;
+
+extern struct notif_server notif_stop;
+
+int handle_notif_ack (char *own_buf, int packet_len);
+void notif_write_event (struct notif_server *notif, char *own_buf);
+
+void notif_push (struct notif_server *np, struct notif_event *event);
+void notif_event_enque (struct notif_server *notif,
+			struct notif_event *event);
+
+#endif /* GDBSERVER_NOTIF_H */