[gnome-applets] window-title: fix -Wmissing-prototypes warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 0462787ef28ee406ccf39a42bc2ce0dd1f19f228
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Tue Mar 10 19:41:54 2020 +0200

    window-title: fix -Wmissing-prototypes warning

 window-title/windowtitle.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/window-title/windowtitle.c b/window-title/windowtitle.c
index 8a6e231ef..e6f340f98 100755
--- a/window-title/windowtitle.c
+++ b/window-title/windowtitle.c
@@ -334,7 +334,9 @@ updateTitle (WTApplet *wtapplet)
 }
 
 /* Expand/unexpand applet according to preferences */
-void toggleExpand(WTApplet *wtapplet) {
+static void
+toggleExpand (WTApplet *wtapplet)
+{
        if (wtapplet->prefs->expand_applet) {
                panel_applet_set_flags (PANEL_APPLET (wtapplet), PANEL_APPLET_EXPAND_MINOR | 
PANEL_APPLET_EXPAND_MAJOR);
        } else {