Hi Guiseppe,
DarwinPorts (now MacPorts) was last tried when 10.4 came out, and
the included version of openmotif was not found to be as stable as
the fink version. Perhaps it has improved since then. But we do
not make a practice of re-testing such things too often, preferring
to find what works well and use it.
If you and others have found that MacPorts seems to be working well,
it is certainly worth noting for the future.
---
As far as how you can download only changed files, one option would
be to use 'wget -m' to mirror the afni:/pub/dist/src directory tree.
We do not currently have a public CVS tree, as far as I know.
- rick