[NTG-context] alloc@0, etc, from plain.tex

There's a plain TeX package (bussproofs.sty from CTAN; I realize that the file ends with ".sty" but it's intended to work in plain TeX) that I'm trying to get working with ConTeXt. I'm stuck at one point though: the package has the statements \def\newcount{\alloc@0\count\countdef\insc@unt} \def\newdimen{\alloc@1\dimen\dimendef\insc@unt} \def\newskip{\alloc@2\skip\skipdef\insc@unt} \def\newbox{\alloc@4\box\chardef\insc@unt} ConTeXt complains because it doesn't know what alloc@0, etc., are. Any advice for how to import this functionality from plain.tex into ConTeXt? thanks, Jesse