Running JACK with realtime priorities

I spent *HOURS* trying to figure out how to use POSIX capabilities unter Linux to run the jack soundserver with realtime priorities. The simple answer to this “how-to” question is: YOU DON'T!. There are many pages describing the various merits of SYS_CAP_NICE and all, a buggy kernel-module that does no longer work on a recent kernel, and even more junk. But the real solution is to just use rlimits. Had I only used GENTOO, most likely, I would have found out earlier. I only found out what to really search for, after stumbling over this page on linuxaudio.org.