AUR has the package celt which I've always had installed (installed it long time back to compile some audio app). http://aur.archlinux.org/packages.php?ID=27117
Repos have celt-0.7 which provides celt.
Thing is, when I try to makepkg jack-audio-connection-kit-mp (which doesn't depend on celt at all) it fails when celt is installed, but works when celt-0.7 or no celt is installed.
There's overlap between AUR packages and other stuff here, so I'm not sure whether this belongs on this ML, or even in a personal email to the maintainer. In which case, my question would be, which maintainer?