diff --git a/config-win32.h b/config-win32.h
index 20e00ca4711238eed37c776a2f37a612c98a7e79..04d58c3ad1770eed235a9d176555c1b0524b7316 100644
--- a/config-win32.h
+++ b/config-win32.h
@@ -166,3 +166,6 @@
 
 /* Define if you have the closesocket function.  */
 #define HAVE_CLOSESOCKET 1
+
+/* Define if you have the setvbuf function.  */
+#define HAVE_SETVBUF 1