Add "new-ui console" tests

This adds a test that uses new-ui to create a secondary console, and
then runs some basic smoke tests.  It ensures that:

 - synchronous commands send output to the UI that initiated it

 - asynchronous events like breakpoint hits are reported on all
   consoles.

 - "new-ui" without arguments doesn't crash.

 - The "new-ui" command doesn't repeat.

gdb/testsuite/ChangeLog:
2016-06-21  Pedro Alves  <palves@redhat.com>

	* gdb.base/new-ui.exp: New file.
	* lib/mi-support.exp (switch_gdb_spawn_id): Move to ...
	* lib/gdb.exp (switch_gdb_spawn_id): ... here.
	(with_spawn_id): New procedure.

1 files changed, 42 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.base/new-ui.c b/gdb/testsuite/gdb.base/new-ui.c
new file mode 100644
index 0000000..8fff0bc
--- /dev/null
+++ b/gdb/testsuite/gdb.base/new-ui.c
@@ -0,0 +1,42 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 Free Software Foundation, Inc.
+
+   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/>.
+
+*/
+
+volatile int global = 0;
+
+int
+main (void)
+{
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1; /* set break main console here */
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1;
+  global = 1; /* set break extra console here */
+  return 0;
+}