diff --git a/plug-ins/imagemap/imap_cern_lex.c b/plug-ins/imagemap/imap_cern_lex.c
index eb761d2b89..b5d595d05a 100644
--- a/plug-ins/imagemap/imap_cern_lex.c
+++ b/plug-ins/imagemap/imap_cern_lex.c
@@ -618,13 +618,16 @@ char *cern_text;
 #define INITIAL 0
 #define comment 1
 
-#ifndef YY_NO_UNISTD_H
+#if !defined(YY_NO_UNISTD_H) && defined(HAVE_UNISTD_H)
 /* Special case for "unistd.h", since it is non-ANSI. We include it way
  * down here because we want the user's section 1 to have been scanned first.
  * The user has a chance to override it with an option.
  */
 #include <unistd.h>
 #endif
+#ifdef _WIN32
+#include <io.h>
+#endif
 
 #ifndef YY_EXTRA_TYPE
 #define YY_EXTRA_TYPE void *
diff --git a/plug-ins/imagemap/imap_csim_lex.c b/plug-ins/imagemap/imap_csim_lex.c
index 178d49fb43..760244c5f9 100644
--- a/plug-ins/imagemap/imap_csim_lex.c
+++ b/plug-ins/imagemap/imap_csim_lex.c
@@ -643,13 +643,16 @@ char *csim_text;
 #define quoted_string 1
 #define comment 2
 
-#ifndef YY_NO_UNISTD_H
+#if !defined(YY_NO_UNISTD_H) && defined(HAVE_UNISTD_H)
 /* Special case for "unistd.h", since it is non-ANSI. We include it way
  * down here because we want the user's section 1 to have been scanned first.
  * The user has a chance to override it with an option.
  */
 #include <unistd.h>
 #endif
+#ifdef _WIN32
+#include <io.h>
+#endif
 
 #ifndef YY_EXTRA_TYPE
 #define YY_EXTRA_TYPE void *
diff --git a/plug-ins/imagemap/imap_ncsa_lex.c b/plug-ins/imagemap/imap_ncsa_lex.c
index 56f2fe1966..87acdc3807 100644
--- a/plug-ins/imagemap/imap_ncsa_lex.c
+++ b/plug-ins/imagemap/imap_ncsa_lex.c
@@ -583,13 +583,16 @@ char *ncsa_text;
 #define imap_link 1
 #define comment 2
 
-#ifndef YY_NO_UNISTD_H
+#if !defined(YY_NO_UNISTD_H) && defined(HAVE_UNISTD_H)
 /* Special case for "unistd.h", since it is non-ANSI. We include it way
  * down here because we want the user's section 1 to have been scanned first.
  * The user has a chance to override it with an option.
  */
 #include <unistd.h>
 #endif
+#ifdef _WIN32
+#include <io.h>
+#endif
 
 #ifndef YY_EXTRA_TYPE
 #define YY_EXTRA_TYPE void *