[atkmm] --enable-warnings=fatal: Use the same warnings as glibmm and gtkmm.

[Murray Cumming <murrayc src gnome org>]

commit fe82851d7152170520b0032ad51b9613aafa89a4
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Oct 27 10:02:18 2015 +0100

    --enable-warnings=fatal: Use the same warnings as glibmm and gtkmm.

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index e3abc8b..79d85ea 100644
--- a/configure.ac
+++ b/configure.ac
@@ -66,7 +66,7 @@ MM_ARG_WITH_TAGFILE_DOC([glibmm-2.4.tag], [glibmm-2.4])
 AC_LANG([C++])
 MM_ARG_ENABLE_WARNINGS([ATKMM_WXXFLAGS],
                        [-Wall],
-                       [-pedantic -Wall -Wextra -Wno-long-long -DGSEAL_ENABLE],
+                       [-pedantic -Wall -Wextra -Wformat-security -Wsuggest-override -Wshadow 
-Wno-long-long],
                        [G ATK GLIBMM])
 
 AC_CONFIG_FILES([Makefile