Support building with -Werror=strict-prototypes / -Werror=old-style-definition

Unfortunately "-std=c99" is not sufficient to make gcc ignore code that
uses constructs of earlier C standards, which were abandoned in C99.

See https://lwn.net/ml/fedora-devel/Y1kvF35WozzGBpc8@redhat.com/ for
some related discussion.

Change-Id: I84fd99442d0cc400fa562fa33623c142649230e2
diff --git a/include/osmocom/vty/command.h b/include/osmocom/vty/command.h
index e3919fb..61b5881 100644
--- a/include/osmocom/vty/command.h
+++ b/include/osmocom/vty/command.h
@@ -442,8 +442,8 @@
 vector cmd_make_strvec(const char *);
 int cmd_make_strvec2(const char *string, char **indent, vector *strvec_p);
 void cmd_free_strvec(vector);
-vector cmd_describe_command();
-char **cmd_complete_command();
+vector cmd_describe_command(vector vline, struct vty *vty, int *status);
+char **cmd_complete_command(vector vline, struct vty *vty, int *status);
 const char *cmd_prompt(enum node_type);
 int config_from_file(struct vty *, FILE *);
 enum node_type node_parent(enum node_type);