Show optimized out local variables in "info locals"

Currently, optimized out variables are not shown when doing "info
locals".  Some users found that confusing, thinking GDB forgot to print
their variable.  This patch adds them to the "info locals" output.  I
added a test in gdb.dwarf2 to test for that behavior.  I think doing a
synthetic DWARF test is the easiest way to have an optimized out local
variable for sure.

However, this change reveals what I think is a bug in GDB, see:

http://lists.dwarfstd.org/pipermail/dwarf-discuss-dwarfstd.org/2017-September/004394.html

This patch marks the tests in inline-locals.exp that start failing as
KFAIL.  I'd like to tackle this bug eventually, but I don't have the
time right now.  I think it's still better to show an extra erroneous
entry than to not show the optimized out variables at all.  I haven't
created a bug in bugzilla yet, but if we agree it's indeed a bug,  I'll
create one and update the setup_kfail lines with the actual bug number
before pushing.

gdb/ChangeLog:

	* stack.c (iterate_over_block_locals): Add LOC_OPTIMIZED_OUT
	case in switch.

gdb/testsuite/ChangeLog:

	* gdb.opt/inline-locals.exp: Mark tests as KFAIL.
	* gdb.dwarf2/info-locals-optimized-out.exp: New file.
	* gdb.dwarf2/info-locals-optimized-out.c: New file.

1 files changed, 23 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.dwarf2/info-locals-optimized-out.c b/gdb/testsuite/gdb.dwarf2/info-locals-optimized-out.c
new file mode 100644
index 0000000..e3ae4cd
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/info-locals-optimized-out.c
@@ -0,0 +1,23 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2017 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/>.  */
+
+int
+main (void)
+{
+  asm ("main_label: .globl main_label");
+  return 0;
+}