[empathy] Build with TP_SEAL_ENABLE

[Guillaume Desmottes <gdesmott src gnome org>]

commit 0c54e7a181b440ef53509aa84c92e586c3d04499
Author: Guillaume Desmottes <guillaume desmottes collabora co uk>
Date:   Thu Jun 7 12:01:35 2012 +0200

    Build with TP_SEAL_ENABLE
    
    https://bugzilla.gnome.org/show_bug.cgi?id=677545

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7c2b7b8..70d3657 100644
--- a/configure.ac
+++ b/configure.ac
@@ -55,6 +55,7 @@ CLUTTER_GST_REQUIRED=1.5.2
 TELEPATHY_GLIB_REQUIRED=0.19.1
 AC_DEFINE(TP_VERSION_MIN_REQUIRED, TP_VERSION_0_20, [Ignore post 0.20 deprecations])
 AC_DEFINE(TP_VERSION_MAX_ALLOWED, TP_VERSION_0_20, [Prevent post 0.20 APIs])
+AC_DEFINE(TP_SEAL_ENABLE, 1, [Prevent to use sealed variables])
 
 GSTREAMER_REQUIRED=0.10.32
 KEYRING_REQUIRED=2.26.0