This is kind of a work in progress. Here's what we've done so far to
build a portable tarball. We keep all the stuff that Citadel needs, but
is not part of Citadel itself, in /usr/local/ctdlsupport, and we keep
-Citadel in /usr/local/citadel.
+Citadel in /usr/local/citadel. (This is only known to work on Linux+GCC.)
We build in /usr/src.