diff --git a/putty.h b/putty.h
index abbb9121..83520f27 100644
--- a/putty.h
+++ b/putty.h
@@ -225,7 +225,7 @@ void term_invalidate(void);
  * Exports from raw.c.
  */
 
-Backend raw_backend;
+extern Backend raw_backend;
 
 /*
  * Exports from telnet.c.