[gnome-desktop] thumbnailer: Fix compile-time error on x32

[Laurent Bigonville <lbigon src gnome org>]

commit 012cad653253ae5f5248988cda89159f22c1fb1d
Author: Laurent Bigonville <bigon bigon be>
Date:   Wed Aug 16 12:04:46 2017 +0200

    thumbnailer: Fix compile-time error on x32
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786355

 libgnome-desktop/gnome-desktop-thumbnail.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgnome-desktop/gnome-desktop-thumbnail.c b/libgnome-desktop/gnome-desktop-thumbnail.c
index 866fc7d..d86d8b1 100644
--- a/libgnome-desktop/gnome-desktop-thumbnail.c
+++ b/libgnome-desktop/gnome-desktop-thumbnail.c
@@ -1116,7 +1116,7 @@ save_thumbnail (GdkPixbuf  *pixbuf,
     goto out;
   close (tmp_fd);
 
-  g_snprintf (mtime_str, 21, "%ld",  mtime);
+  g_snprintf (mtime_str, 21, "%" G_GINT64_FORMAT, (gint64) mtime);
   width = gdk_pixbuf_get_option (pixbuf, "tEXt::Thumb::Image::Width");
   height = gdk_pixbuf_get_option (pixbuf, "tEXt::Thumb::Image::Height");