@@ -970,10 +970,11 @@
 		;;
 	esac
 
 	AC_DEFINE(OF_HAVE_THREADS, 1, [Whether we have threads])
 	AC_SUBST(USE_SRCS_THREADS, '${SRCS_THREADS}')
+	AC_SUBST(OBJC_SYNC, objc_sync)
 
 	AC_ARG_ENABLE(compiler-tls,
 		AS_HELP_STRING([--disable-compiler-tls],
 			[disable compiler thread local storage]))