diff --git a/nt/config.nt b/nt/config.nt
index e0b97f0e491..cbc3b198ebc 100644
--- a/nt/config.nt
+++ b/nt/config.nt
@@ -233,7 +233,7 @@ Boston, MA 02111-1307, USA.  */
 #undef HAVE_SHUTDOWN
 #undef HAVE_STRFTIME
 
-#undef LOCALTIME_CACHE
+#define LOCALTIME_CACHE
 #undef HAVE_INET_SOCKETS
 
 #undef HAVE_AIX_SMT_EXP