The FreeBSD build broke on 'Package bzip2, required by freetype2, not found': freetype2.pc lists bzip2 as a (private) requirement, but no bzip2.pc was installed, so pkg-config could not generate cflags for gtkmm-3.0. Add bzip2 to the package list.
The FreeBSD build broke on 'Package bzip2, required by freetype2, not found': freetype2.pc lists bzip2 as a (private) requirement, but no bzip2.pc was installed, so pkg-config could not generate cflags for gtkmm-3.0. Add bzip2 to the package list.