@@ -50,10 +50,14 @@
 	AC_DEFINE(OF_APPLE_RUNTIME, 1, [Whether we use the Apple ObjC runtime])
 	AC_SUBST(RUNTIME_DEF, "-DOF_APPLE_RUNTIME")
 	objc_runtime="Apple"])
 AC_MSG_RESULT($objc_runtime)
 
+AC_CHECK_FUNC(objc_enumerationMutation, [
+	AC_DEFINE(HAVE_OBJC_ENUMERATIONMUTATION, 1,
+		[Whether we have objc_enumerationMutation])])
+
 BUILDSYS_LIB
 AC_DEFINE_UNQUOTED(PLUGIN_SUFFIX, "$PLUGIN_SUFFIX", [Suffix for plugins])
 if test x"$PLUGIN_SUFFIX" != "x"; then
 	AC_SUBST(OFPLUGIN_M, "OFPlugin.m")
 	AC_SUBST(TESTPLUGIN, "plugin")