Building for GNUSTEP

[George]

Hello,

I'd like to build emacs for my favorite tookit, GNUSTEP, however the 
manual does not give any instructions on how to produce a usable emacs.app.

The following resource pointed me to this mailing list: 
https://www.gnu.org/software/emacs/manual/html_node/efaq/Emacs-for-GNUstep.html

If anybody knows how to build for GNUSTEP, let me know.

Thanks