[goocanvasmm] configure.ac: Use more warnings, like gtkmm.

[Murray Cumming <murrayc src gnome org>]

commit d22c4d70d1af6b97293711cbafb5fcd52119ffe9
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Jul 29 14:27:21 2015 +0200

    configure.ac: Use more warnings, like gtkmm.

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index abc750a..968ff10 100644
--- a/configure.ac
+++ b/configure.ac
@@ -64,8 +64,8 @@ MM_ARG_WITH_TAGFILE_DOC([gtkmm-3.0.tag], [gtkmm-3.0])
 AC_LANG([C++])
 MM_ARG_ENABLE_WARNINGS([GOOCANVASMM_WXXFLAGS],
                        [-Wall],
-                       [-pedantic -Wall -Wextra  -Wno-long-long -DGSEAL_ENABLE],
-                       [G PANGO ATK GDK GDK_PIXBUF GTK GLIBMM ATKMM PANGOMM CAIROMM])
+                       [-pedantic -Wall -Wextra -Wformat-security-Wno-long-long -DGSEAL_ENABLE],
+                       [G PANGO ATK GDK GDK_PIXBUF GTK SIGC GLIBMM ATKMM PANGOMM CAIROMM GTKMM])
 
 AC_CONFIG_FILES([Makefile
                  codegen/Makefile