In order to get the documentation to build on MacOS X, I had to make this adjustment:
In xdocs/sources/make-xalan.sh, replace:
We need to know what the BUILDPATH is though. Could this script file be renamed to make-xalan.sh.in and generated by configure with the correct build path embedded?
While this is an issue on MacOS X, it's likely also an issue on Linux and BSD, where LD_LIBRARY_PATH needs setting to allow the Xalan binary to run. Unless that's already taken care of, and DYLD_LIBRARY_PATH could be set there as well.