emacs under Cygwin

[Paminu]

I just downloaded emacs 21.4a from:

http://ftp.gnu.org/pub/gnu/emacs/

I unzipped it to my home dir in c:\cygwin and opened a shell and entered the 
dir and typed ./configure. But then I get this error:

configure: error: Emacs hasn't been ported to 'i686-pc-cygwin' systems.

Is there no way to install emacs under cygwin?

I would prefer to build a native linux version under Cygwin instead of 
installing the windows version.