diff --git a/lib/config.dos b/lib/config.dos
index dbd8e6342fe1777aa8b1be1dc8cbf51cb99134fc..5cf4863eb24ccc3bd5a6c2a0d811c17e8781836d 100644
--- a/lib/config.dos
+++ b/lib/config.dos
@@ -39,6 +39,7 @@
 #define HAVE_SEND              1
 #define HAVE_SETJMP_H          1
 #define HAVE_SETLOCALE         1
+#define HAVE_SETMODE           1
 #define HAVE_SIGNAL            1
 #define HAVE_SOCKET            1
 #define HAVE_SPNEGO            1