diff --git a/src/toolsComm/flex/flexdef.h b/src/toolsComm/flex/flexdef.h
index 3cdab75e3..6991dc0dd 100644
--- a/src/toolsComm/flex/flexdef.h
+++ b/src/toolsComm/flex/flexdef.h
@@ -876,5 +876,7 @@ extern int yylex PROTO(());
 /* The Unix kernel calls used here */
 
 extern int read PROTO((int, char*, int));
+#ifndef _WIN32
 extern int unlink PROTO((char*));
+#endif
 extern int write PROTO((int, char*, int));