To compile Mixxx CVS (1.5.x) on FreeBSD, follow the patches in ports/mixxx (which is on Mixxx 1.4). Basically, we need a whole bunch of ifdefs for FreeBSD. Also, I had to take of the permissions on /dev/midistat as the device polling makes Mixxx too slow.
Am not sure why Mixxx does not like the midi device on FreeBSD much.
> grep midi /etc/devfs.conf
# mixxx/midi slows down, make it non-accessible
perm midistat 0600
> cat /usr/ports/audio/mixxx/pkg-descr
Mixxx is software for DJ'ing. You can use wave based audio files, Ogg
Vorbis and MP3 files as audio input. Mixxx can be controlled through
the GUI and with external controllers including MIDI devices,
joysticks and more.
– Jean-Yves Lefort