diff --git a/src/dos/dos_programs.cpp b/src/dos/dos_programs.cpp
index 4086b167..0b9efbe0 100644
--- a/src/dos/dos_programs.cpp
+++ b/src/dos/dos_programs.cpp
@@ -46,6 +46,12 @@
 #include "os2.h"
 #endif
 
+#if defined(WIN32)
+#ifndef S_ISDIR
+#define S_ISDIR(m) (((m)&S_IFMT)==S_IFDIR)
+#endif
+#endif
+
 #if C_DEBUG
 Bitu DEBUG_EnableDebugger(void);
 #endif