diff --git a/src/config.in b/src/config.in
index 22646cb4397..54b27d2a7a8 100644
--- a/src/config.in
+++ b/src/config.in
@@ -137,7 +137,6 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #undef TM_IN_SYS_TIME
 #undef HAVE_TM_ZONE
 #undef HAVE_TZNAME
-#undef LOCALTIME_CACHE
 
 #undef const