I have just compiled an static version of glib-2.38.2 and fluidsynth-1.1.6 in order to easily add support for MIDI files to VLC-2.1.1 under OSX. If you want it you can get the plugin here. You will also need a SoundFont in .sf2 format, as this or this. For installation uncompress the .xz and copy it to
VLC.app/Contents/MacOS/plugins/ put the .sf2 file somewhere and add a reference to it under Preferences(All)/InputCodecs/Audio Codecs/FluidSynth
If FluidSynth does not appear under AudioCodecs try to reset the VLC Plugin Cache with
You can test it with for example this quite acceptable MIDI file.
Hope it helps!
UPDATE: It seems that VLC 2.2 changed library compatibility, recompiled against glib-2.44.1 and VLC-2.2.0 under OS X 10.10.4: libfluidsynth_plugin-2.2.dylib.xz