libGLU and headers are included in Solaris releases that
include the SUNWxorg-mesa package.
If you are using a Solaris release that does not yet have the
SUNWxorg-mesa package you can grab this version:
Note: the libGLw in this image will be binary incompatible with
what gets eventually bundled in Solaris. (GLU is fine).
Also, GLUT is available at: