[XForms] xforms and Ygl

[vwf]

Hello,

I have some old programs made for SGI. They use (an old version of)
XForms and GL. The XForms version was Version 2.1 c (Date:  Oct  6,
1992). Some functions were replaced by others, the warnings are numerous
(pointer problems), but an executable is made.

Can I simply switch from XForms 2.1 c to xforms-1.0.92 or are some
serious modifications needed to make it work?

GL is replaced by Ygl. The executable crashes on a gl problem. XForms
depends on gl, but this is not Ygl. 

Do I need to make a special build of XForms to use Ygl, or can XForms
run using OpenGL? 

Thank you,
Frits