problem building libwww "world.dsw" from visual studio?

I am running into immediate problems with building libwww from visual
studio. Note that a visual studio dsw is readily available with the
downloadable w3c-libwww-5.4.0.zip and there is a =93world=94 soln project.

However, regex.h is not available according to error output.

 I am not using nor intend using cygwin. Besides this should build off
the bat since the libwww people have added a world.dsw/sol file
anyway.
How can i get/what do i need to do to get build going?