Add "signal SIGTRAP" test

Some local changes I was working on related to SIGTRAP handling
resulted in "signal SIGTRAP" no longer passing the SIGTRAP to the
inferior.

Surprisingly, only annota1.exp catches this.  This commit adds a test
that doesn't rely on annotations, so that at the point annotations are
finaly dropped, we still have this use case covered ...

This is a multi-threaded test to also exercise the case of first
needing to do a step-over before delivering the signal.

Tested on x86_64 Fedora 20, native, remote/extended-remote gdbserver.

gdb/testsuite/
2015-02-10  Pedro Alves  <palves@redhat.com>

	* gdb.threads/signal-sigtrap.c: New file.
	* gdb.threads/signal-sigtrap.exp: New file.

1 files changed, 46 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.threads/signal-sigtrap.c b/gdb/testsuite/gdb.threads/signal-sigtrap.c
new file mode 100644
index 0000000..4513d38
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/signal-sigtrap.c
@@ -0,0 +1,46 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014-2015 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/>.  */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <signal.h>
+
+void
+sigtrap_handler (int sig)
+{
+}
+
+void *
+thread_function (void *arg)
+{
+  return NULL;
+}
+
+int
+main (void)
+{
+  pthread_t child_thread;
+
+  signal (SIGTRAP, sigtrap_handler);
+
+  pthread_create (&child_thread, NULL, thread_function, NULL);
+
+  pthread_join (child_thread, NULL);
+
+  return 0;
+}