diff --git a/lib/config-win32.h b/lib/config-win32.h
index 8b488c1c1..d19665d71 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -183,7 +183,7 @@
 /* #define HAVE_DOPRNT 1 */
 
 /* Define if you have the ftruncate function. */
-#define HAVE_FTRUNCATE 1
+/* #define HAVE_FTRUNCATE 1 */
 
 /* Define to 1 if you have the `getpeername' function. */
 #define HAVE_GETPEERNAME 1