more C standard compat fixes from Dan Fandrich

function                                             old     new   delta
docolon                                              207     204      -3

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/miscutils/dc.c b/miscutils/dc.c
index ff2bc3b..3656cdd 100644
--- a/miscutils/dc.c
+++ b/miscutils/dc.c
@@ -182,7 +182,7 @@
 	{"p", print_no_pop},
 	{"f", print_stack_no_pop},
 	{"o", set_output_base},
-	{ /* zero filled */ }
+	{ "", NULL }
 };
 
 static void stack_machine(const char *argument)