diff --git a/gzguts.h b/gzguts.h
index 07c7ac3..48bd98f 100644
--- a/gzguts.h
+++ b/gzguts.h
@@ -27,7 +27,7 @@
 #endif
 #include <fcntl.h>
 
-#if defined(MSDOS) && defined(__TURBOC__)
+#ifdef __TURBOC__
 #  include <io.h>
 #endif