on darwin configure script picks up private per-user tmp directory
in /var/folders/xx/...+++... via the TMPDIR environment and cheerfully
installs it in /usr/pkg/etc/dbus-1/session.conf meaning that only the
user who installed the package will be able to write to that directory...
except that dbus rejects directories with "+"'s in the filename so it
won't work anyway.  use configure --with-session-socket-dir=/tmp
to work around this.  found a description of this issue here:
http://wiki.gnucash.org/wiki/MacOSX/Quartz in the
"Running from the commandline" section.

dbus also cannot cope with $DISPLAY containing "/" chars (like in
darwin ... /tmp/launch-kcvznx/:0 ) so get rid of the ":" as described
here:
https://trac.macports.org/attachment/ticket/16833/patch-dbus-launch-x11.c.diff

(chuck)