Exit code of exited inferiors in -list-thread-groups

Don't reset the exit code at inferior exit and print it in
-list-thread-groups.

gdb/ChangeLog:

	* NEWS: Announce new exit-code field in -list-thread-groups
	output.
	* inferior.c (exit_inferior_1): Don't clear exit code.
	(inferior_appeared): Clear exit code.
	* mi/mi-main.c (print_one_inferior): Add printing of the exit
	code.

gdb/testsuite/ChangeLog:

	* gdb.mi/mi-exit-code.exp: New file.
	* gdb.mi/mi-exit-code.c: New file.

gdb/doc/ChangeLog:

	* gdb.texinfo (Miscellaneous gdb/mi Commands): Document new
	exit-code field in -list-thread-groups output.

1 files changed, 5 insertions, 0 deletions

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 026706a..429c650 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -31152,6 +31152,11 @@ valid type.
 The target-specific process identifier.  This field is only present
 for thread groups of type @samp{process} and only if the process exists.
 
+@item exit-code
+The exit code of this group's last exited thread, formatted in octal.
+This field is only present for thread groups of type @samp{process} and
+only if the process is not running.
+
 @item num_children
 The number of children this thread group has.  This field may be
 absent for an available thread group.