diff --git a/hl/src/lex.yy.c b/hl/src/lex.yy.c
index 4917c21904..74213ddd4c 100644
--- a/hl/src/lex.yy.c
+++ b/hl/src/lex.yy.c
@@ -23,7 +23,7 @@
 #define YY_FLEX_MINOR_VERSION 5
 
 #include <stdio.h>
-#ifdef H5_HAVE_UNISTD_H
+#ifndef WIN32
 #include <unistd.h>
 #endif