--- a/configure.in
+++ b/configure.in
@@ -29,7 +29,7 @@
 EXTERN_CXXFLAGS="$CXXFLAGS"
 
 AC_INIT
-AC_REVISION($Revision: 1.530 $)
+AC_REVISION($Revision: 1.532 $)
 AC_PREREQ(2.57)
 AC_CONFIG_SRCDIR([src/octave.cc])
 AC_CONFIG_HEADER(config.h)
@@ -38,6 +38,22 @@
 
 AC_DEFINE(OCTAVE_SOURCE, 1, [Define if this is Octave.])
   
+dnl FIXME -- we should probably only generate this file if it is missing.
+### Produce unistd.h for MSVC target, this simplifies changes in
+### Octave source tree and avoid problems with lex-generated code.
+case "$canonical_host_type" in
+  *-*-msdosmsvc)
+    AC_MSG_NOTICE([Generating replacement for <unistd.h> for MSVC])
+    cat << \EOF > unistd.h
+/* File generated by configure script. */
+#include <direct.h>
+#include <io.h>
+#include <process.h>
+EOF
+    CPPFLAGS="-I. $CPPFLAGS"
+    ;;
+esac
+
 AC_GNU_SOURCE
 
 AC_AIX
@@ -52,7 +68,7 @@
 case $with_sepchar in
   yes | "")
     case "$canonical_host_type" in
-      *-*-mingw*)
+      *-*-mingw* | *-*-msdosmsvc)
 	sepchar=';'
         ;;
       esac