diff --git a/src/syncterm/telnet_io.c b/src/syncterm/telnet_io.c
index 81acc371e145a5aa16c9b8f4cadf49df3ae3481a..8e31fe198111226d3fd3f2a949eccc0c7bf56dce 100644
--- a/src/syncterm/telnet_io.c
+++ b/src/syncterm/telnet_io.c
@@ -9,7 +9,9 @@
 
 #include "genwrap.h"
 #include "sockwrap.h"
+#ifndef TELNET_NO_DLL
 #define TELNET_NO_DLL
+#endif
 #include "telnet.h"
 #include "gen_defs.h"
 #include "bbslist.h"
diff --git a/src/syncterm/telnet_io.h b/src/syncterm/telnet_io.h
index 9e98fea4f2f85bad51b0bc9025b3e4b9dc7bd297..5dd0547c188a7096c70ebac85c6c938f00174bac 100644
--- a/src/syncterm/telnet_io.h
+++ b/src/syncterm/telnet_io.h
@@ -5,7 +5,9 @@
 #ifndef _TELNET_IO_H_
 #define _TELNET_IO_H_
 
+#ifndef TELNET_NO_DLL
 #define TELNET_NO_DLL
+#endif
 #include "telnet.h"
 
 extern uchar	telnet_local_option[0x100];