MSVC compiler support [patch 3]: Local unistd.h creation

[Michael Goffioul]

Defines an equivalent unistd.h: easier to port octave code, and flex 
generates code
that include unistd.h unconditionally

Index: configure.in
===================================================================
RCS file: /cvs/octave/configure.in,v
retrieving revision 1.526
diff -p -c -r1.526 configure.in
*** configure.in        13 Oct 2006 18:11:26 -0000      1.526
--- configure.in        17 Oct 2006 11:07:41 -0000
*************** OCTAVE_HOST_TYPE
*** 38,43 ****
--- 38,57 ----
  
  AC_DEFINE(OCTAVE_SOURCE, 1, [Define if this is Octave.])
    
+ ### 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
+   *-*-msdos)
+     AC_MSG_NOTICE([Producing standard header <unistd.h> for MSVC])
+     cat << \EOF > unistd.h
+ /* File generated by configure script */
+ #include <io.h>
+ #include <process.h>
+ EOF
+     CPPFLAGS="-I. $CPPFLAGS"
+     ;;
+ esac
+ 
  AC_GNU_SOURCE
  
  AC_AIX
Index: octMakefile.in
===================================================================
RCS file: /cvs/octave/octMakefile.in,v
retrieving revision 1.212
diff -p -c -r1.212 octMakefile.in
*** octMakefile.in      28 Jul 2006 17:06:15 -0000      1.212
--- octMakefile.in      17 Oct 2006 11:07:41 -0000
*************** maintainer-clean distclean::
*** 146,151 ****
--- 146,152 ----
        rm -f config.cache config.h config.log config.status
        rm -rf autom4te.cache
        rm -f $(SHELL_SCRIPTS) .gdbinit
+       rm -f unistd.h
  
  maintainer-clean::
        rm -f configure config.h.in BUGS INSTALL.OCTAVE