[balsa] abook-completion: Add a second argument

[Peter Bloomfield <peterb src gnome org>]

commit 90ba3f1ff12be02b93ad66d601f8eedcd54ae420
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Wed Jun 12 20:05:00 2019 -0400

    abook-completion: Add a second argument
    
    abook-completion: Add a second "gpointer unused" argument to
    completion_data_free(…) so that it can be cast to "GFunc" without
    raising -Wcast-function-type.

 libbalsa/abook-completion.c | 2 +-
 libbalsa/abook-completion.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/libbalsa/abook-completion.c b/libbalsa/abook-completion.c
index bf9d7a5fd..0efbd13ae 100644
--- a/libbalsa/abook-completion.c
+++ b/libbalsa/abook-completion.c
@@ -75,7 +75,7 @@ completion_data_new(InternetAddress * ia, const gchar * nick_name)
  * Free a CompletionData
  */
 void
-completion_data_free(CompletionData * data)
+completion_data_free(CompletionData * data, gpointer unused G_GNUC_UNUSED)
 {
     g_object_unref(data->ia);
     g_free(data->string);
diff --git a/libbalsa/abook-completion.h b/libbalsa/abook-completion.h
index dc0169724..f84744b39 100644
--- a/libbalsa/abook-completion.h
+++ b/libbalsa/abook-completion.h
@@ -35,7 +35,7 @@ struct _CompletionData {
 
 CompletionData *completion_data_new(InternetAddress * ia,
                                     const gchar * nick_name);
-void completion_data_free(CompletionData * data);
+void completion_data_free(CompletionData * data, gpointer unused);
 gchar *completion_data_extract(CompletionData * data);
 gint strncmp_word(const gchar * s1, const gchar * s2, gsize n);