[balsa] Fix the build

[Peter Bloomfield <peterb src gnome org>]

commit 9cd723c43d9f084ea9ed32f7e4228e837650625b
Author: Albrecht Dreß <albrecht dress arcor de>
Date:   Thu Apr 18 16:22:42 2019 -0400

    Fix the build
    
    Fix the build after commit e92ec3140a1c81dbf86d90d0155cb2e08f519db2
    
    * src/main-window.c (bw_update_progress_bar): cast with
      '(GSourceFunc)', not with 'G_SOURCE_FUNC()', since we do not yet
      require GLib 2.58!

 ChangeLog         | 10 +++++++++-
 src/main-window.c |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 259077e0f..653d59768 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,12 @@
-2019-04-18  Peter Bloomfield  <pbloomfield bellsouth net>
+2019-04-18  Albrecht Dreß  <albrecht dress arcor de>
+
+       Fix the build after commit e92ec3140a1c81dbf86d90d0155cb2e08f519db2
+
+       * src/main-window.c (bw_update_progress_bar): cast with
+       '(GSourceFunc)', not with 'G_SOURCE_FUNC()', since we do not yet
+       require GLib 2.58!
+
+2019-04-18  Albrecht Dreß  <albrecht dress arcor de>
 
        geometry-manager: Remove a not-reached assertion
 
diff --git a/src/main-window.c b/src/main-window.c
index ea09784e3..c941e6448 100644
--- a/src/main-window.c
+++ b/src/main-window.c
@@ -4443,7 +4443,7 @@ bw_update_progress_bar(BalsaWindow *window,
     info->set_fraction = set_fraction;
     info->fraction = fraction;
 
-    g_idle_add(G_SOURCE_FUNC(bw_update_progress_bar_idle_cb), info);
+    g_idle_add((GSourceFunc) bw_update_progress_bar_idle_cb, info);
 }
 
 static void