[atkmm] configure.ac: Re-enable deprecation warnings as errors.

[Murray Cumming <murrayc src gnome org>]

commit dff6d64e2a049d281bfb006aba021d9473b45646
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Jun 29 10:13:53 2015 +0200

    configure.ac: Re-enable deprecation warnings as errors.
    
    When using --enable-warnings=fatal.

 codegen/extradefs/generate_extra_defs_atk.cc |    4 ++++
 configure.ac                                 |    2 +-
 2 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/codegen/extradefs/generate_extra_defs_atk.cc b/codegen/extradefs/generate_extra_defs_atk.cc
index 2b678e7..dee866e 100644
--- a/codegen/extradefs/generate_extra_defs_atk.cc
+++ b/codegen/extradefs/generate_extra_defs_atk.cc
@@ -35,6 +35,8 @@ int main(int, char**)
 
   void *const g_class_atk_no_op_object = g_type_class_ref(ATK_TYPE_NO_OP_OBJECT);
 
+G_GNUC_BEGIN_IGNORE_DEPRECATIONS
+
   std::cout << get_defs(ATK_TYPE_OBJECT)
             << get_defs(ATK_TYPE_COMPONENT)
             << get_defs(ATK_TYPE_ACTION)
@@ -57,6 +59,8 @@ int main(int, char**)
             << get_defs(ATK_TYPE_STATE_SET)
             ;
 
+G_GNUC_END_IGNORE_DEPRECATIONS
+
   g_type_class_unref(g_class_atk_no_op_object);
   return 0;
 }
diff --git a/configure.ac b/configure.ac
index a03e1c2..dfee2a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -64,7 +64,7 @@ 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 -Wno-error=deprecated-declarations 
-DGSEAL_ENABLE],
+                       [-pedantic -Wall -Wextra -Wno-long-long -DGSEAL_ENABLE],
                        [G ATK GLIBMM])
 
 AC_CONFIG_FILES([Makefile