ISM-making

Heyo.

When I try to gmake CERL's contributed ISM, I am getting the error message:

main.c: 7 Can't find include file gl.h

There are 2 Sun systems here and neither one seems to have gl.h. Does anyone
have an idea what gl.h is and/or why we don't have it? Should it be very
"standard"?

Thanks for any info.

-nancy

ngreeley@hanover-crrel.army.mil