[Fractdev] bit 2 of user float flag

There is some coe in line3d.c that sets and clears this bit, but apparently noone else pays attention to it except as a side effect of comparing user float flag to 1 or 0. What's the purpose of this second bit? Otherwise user float flag looks like a boolean. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>