[vala] readline: fix the signature of CompletionFunc

[Evan Nemerson <evann src gnome org>]

commit 87b4b42523f130976ca548b93011b9cfa70746bd
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Tue Sep 7 16:37:00 2010 +0100

    readline: fix the signature of CompletionFunc

 vapi/readline.vapi |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/vapi/readline.vapi b/vapi/readline.vapi
index ece78c6..c0335cc 100644
--- a/vapi/readline.vapi
+++ b/vapi/readline.vapi
@@ -25,8 +25,8 @@ namespace Readline {
 
 	[CCode (cname = "rl_command_func_t", has_target = false)]
 	public delegate int      CommandFunc (int a, int b);
-	[CCode (cname = "rl_completion_func_t", has_target = false)]
-	public delegate string[] CompletionFunc (string str, int a, int b);
+	[CCode (cname = "rl_completion_func_t", has_target = false, array_length = false, array_null_terminated = true)]
+	public delegate string[]? CompletionFunc (string str, int a, int b);
 	[CCode (cname = "rl_quote_func_t", has_target = false)]
 	public delegate string?  CompentryFunc (string str, int a);
 	[CCode (cname = "rl_quote_func_t", has_target = false)]