-- pkg_info | grep musicbrainz --

libmusicbrainz-2.1.1 2nd generation incarnation of the CD Index - audio metadata
libtunepimp-0.3.0_1 Client library for musicbrainz

-- paste of some lines of configure --

checking for ov_info in -lvorbisfile... yes
checking for FLAC__metadata_object_new in -lFLAC... yes
checking for mb_GetVersion in -lmusicbrainz... no
*
*  The MusicBrainz client library needs to be installed
*  to build this plugin. Please download the library from
*  http://www.musicbrainz.org/download
*
configure: error: "Cannot build. Stop."
===>  Script "configure" failed unexpectedly.
Please report the problem to lauri@kde.org [maintainer] and attach the
"/usr/ports/audio/libtunepimp/work/libtunepimp-0.3.0/config.log" including
the output of the failure of your make command. Also, it might be a good idea
to provide an overview of all packages installed on your system (e.g. an `ls
/var/db/pkg`).
*** Error code 1