Hi,
this is more a heads up than an actual patch, though I'll attach one ;)
In an attempt to reduce the number of dependencies in Debian, the fltk-library (or more precisely: fltk-config) doesn't include "-lGLU" in its output anymore. This means that octplot won't compile on Debian at the moment (and pretty soon on the derived distributions as well, unless they revert this change, which I consider unlikely). Some information and further links can be found at
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=405233
As this is a Debian-specific change, I don't know if you want to apply the patch. It checks for the GLU-library and uses it. I've found the patch sufficient for compilation on Debian, but didn't test it extensively.
The actual .m4 files are coming from the autoconf-archive project. At least one of them needs the config.guess and config.sub files, so I included them as well.
Link against GLU