[HOpenGL] Texture3D redbook example not working

[Mark Zander]

Hi,

I ran the Texture3D.hs redbook example from GLUT/examples/RedBook.  
After removing the initial check for error I got the following error  
from the program:

Texture3D: user error (unknown OpenGL call glTexImage3DEXT, check for  
GL_EXT_texture3D or OpenGL 1.2)

I've run the texture3D.c redbook example successfully and see the two  
colored rectangles displayed successfully. By the way I noticed that  
the .c code calls glTexImage3D, no EXT used.

I'm running opengl 2.0.

Mark