[vala] readline: Make the parameter of VcpFunc be nullable

[Luca Bruno <lucabru src gnome org>]

commit a346efe47fc77b83770afbb4937eb4da3ba3b091
Author: Philip Withnall <philip tecnocode co uk>
Date:   Fri Jan 13 19:31:32 2012 +0000

    readline: Make the parameter of VcpFunc be nullable
    
    Fixes bug 667893.

 vapi/readline.vapi |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/vapi/readline.vapi b/vapi/readline.vapi
index e130fef..6ff09fd 100644
--- a/vapi/readline.vapi
+++ b/vapi/readline.vapi
@@ -54,7 +54,7 @@ namespace Readline {
 	[CCode (cname = "rl_vintfunc_t", has_target = false)]
 	public delegate void     VintFunc (int a);
 	[CCode (cname = "rl_vcpfunc_t", has_target = false)]
-	public delegate void     VcpFunc (string s);
+	public delegate void     VcpFunc (string? s);
 	[CCode (cname = "rl_vcppfunc_t", has_target = false)]
 	public delegate void     VcppFunc (string[] s);
 	[CCode (cname = "rl_cpvfunc_t", has_target = false)]