[R] Building XML library on MacOS X

[Sean Davis]

This is not a strictly R question, but I am trying to build the XML
package on MacOS X and have not been successful.  I have tried using
expat, libxml, and libxml2 without success in building.  Has someone
successfully done this that could enlighten me with the process
(especially as it relates to installing a libxml version and then
completing the XML package installation, specifying the correct
environment variables, etc.)?

Thanks in advance,
Sean