[vala] codegen: Fix C warning when passing lambda free functions

[Luca Bruno <lucabru src gnome org>]

commit 684b10c4746f77fe424be7bd6d2c15b8bfaa1dbf
Author: Luca Bruno <lucabru src gnome org>
Date:   Mon Feb 6 22:37:16 2012 +0100

    codegen: Fix C warning when passing lambda free functions
    
    Fixes bug 663651.

 codegen/valaccodebasemodule.vala |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 54238d7..9d7395e 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -1910,11 +1910,12 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 			cfile.add_function (ref_fun);
 
 			var unref_fun = new CCodeFunction ("block%d_data_unref".printf (block_id), "void");
-			unref_fun.add_parameter (new CCodeParameter ("_data%d_".printf (block_id), struct_name + "*"));
+			unref_fun.add_parameter (new CCodeParameter ("_userdata_", "void *"));
 			unref_fun.modifiers = CCodeModifiers.STATIC;
 			
 			push_function (unref_fun);
 
+			ccode.add_declaration (struct_name + "*", new CCodeVariableDeclarator ("_data%d_".printf (block_id), new CCodeCastExpression (new CCodeIdentifier ("_userdata_"), struct_name + "*")));
 			ccall = new CCodeFunctionCall (new CCodeIdentifier ("g_atomic_int_dec_and_test"));
 			ccall.add_argument (new CCodeUnaryExpression (CCodeUnaryOperator.ADDRESS_OF, new CCodeMemberAccess.pointer (new CCodeIdentifier ("_data%d_".printf (block_id)), "_ref_count_")));
 			ccode.open_if (ccall);