ospfd: compile warning cleanups

A set of patches to clarify some comments as well as cleanup code that was
causing warnings.  After these patches, the code can be compiled with

-Wall -Wsign-compare -Wpointer-arith -Wbad-function-cast -Wwrite-strings
-Wmissing-prototypes -Wmissing-declarations -Wchar-subscripts -Wcast-qual
-Wextra -Wno-unused-parameter -Wno-missing-field-initializers

(what is current in trunk plus -Wextra -Wno-unused-parameter
-Wno-missing-field-initializers).

Signed-off-by: Scott Feldman <sfeldma@cumulusnetworks.com>
diff --git a/ospfd/ospf_zebra.h b/ospfd/ospf_zebra.h
index fbb3444..148f652 100644
--- a/ospfd/ospf_zebra.h
+++ b/ospfd/ospf_zebra.h
@@ -54,7 +54,7 @@
 				    int *);
 extern int ospf_distribute_check_connected (struct ospf *,
 					    struct external_info *);
-extern void ospf_distribute_list_update (struct ospf *, int);
+extern void ospf_distribute_list_update (struct ospf *, uintptr_t);
 
 extern int ospf_is_type_redistributed (int);
 extern void ospf_distance_reset (struct ospf *);