documentation does not build / configure.ac

[chloros]

I know that there is no guarantee that the current development tip can
be built. If this email is unnecessary, then please kindly just ignore
it. However, before it gets lost, here is some information:

Build freezes at this point:
/bin/sh run-octave --norc --silent --no-history --path 
/home/.../doc/interpreter/ --eval "geometryimages ('doc/interpreter/', 
'voronoi', 'eps');"

Problem:
debug> error: gl2ps_print: support for gl2ps was unavailable or
disabled when Octave was built
error: called from
    __opengl_print__ at line 206 column 9
    print at line 759 column 16
    geometryimages at line 63 column 5

If I move the gl2ps block in configure.ac to about line 2000, the
documentation is build successfully. I think the point is that
$opengl_graphics is used before it is set.