Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -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")

Index: src/OFObject.m
==================================================================
--- src/OFObject.m
+++ src/OFObject.m
@@ -45,10 +45,14 @@
 } alloc_failed_exception;
 
 #ifdef NEED_OBJC_SYNC_INIT
 extern BOOL objc_sync_init();
 #endif
+
+#ifndef HAVE_OBJC_ENUMERATIONMUTATION
+#define enumeration_mutation_handler objc_enumerationMutation
+#endif
 
 void
 enumeration_mutation_handler(id object)
 {
 	@throw [OFEnumerationMutationException newWithClass: [object class]];