Hi Ryan, again, thanks for your help, it works ;-)
You don't need to specify the directory name; MacPorts knows it's going to be in the files directory. Also, your patchfile name should begin with "patch-" and end with ".diff", between which should be the name of the file that's being patched. So if your patch is patching a file called qwtconfig.pri, then you should call the file "patch-qwtconfig.pri.diff", put it in the "files" directory in your port's directory, and put "patchfiles patch- qwtconfig.pri.diff" in the portfile.
I have now tested and uploaded the Portfile and patch to the Trac system. Is there anything I should do in order to get the port included? What's about previous Portfiles I have added there - how often should I bug whom? Greetings, Jochen -- Einigkeit und Recht und Freiheit http://www.Jochen- Kuepper.de Liberté, Égalité, Fraternité GnuPG key: CC1B0B4D Sex, drugs and rock-n-roll