While editors/psgml builds under Emacs 24.x, it doesn't actually work, erroring out when psgml-mode is invoked because Emacs 24.x does not have a "make-local-hook" function. There seems to be a version 1.4 of psgml-mode which is in Debian and does claim to work under Emacs 24, but I was not able to get it to build within the framework of the current port (I didn't try too hard); at a minimum our patches need to be regenerated and/or dropped.
Over to maintainer.
Thank you for your report. This problem should be fixed in r401319. Although this port already had necessary changes to support Emacs 24, some patches were not actually applied due to a bug in Makefile.