Revision 358951 of ports/graphics/libdmtx/Makefile changed the libMagickWand sofile to libMagickWand.so. The ImageMagick port does not provide this file (http://svnweb.freebsd.org/ports/head/graphics/ImageMagick/pkg-plist?view=markup#l424), and I'm not sure how Dmitry determined that it does. I don't see anything in UPDATING about this, either.
libMagickWand library does exist, but its name now contains additions depending on two options. They are set in the ImageMagick port, see graphics/ImageMagick/pkg-plist: lib/libMagickWand-6.%%QBIT%%%%HDRI%%.so So in my case, with options '16BIT_PIXEL' and 'HDRI' set, it gives a libraries name libMagickWand-6.Q16HDRI.so. Note, that both options are declared as 'half supported options' in the graphics/ImageMagick port.
Well, I do have 16BIT_PIXEL=on, but `pkg info -l ImageMagick-6.8.9.3_2,1 | grep libMagickWand` prints: /usr/local/lib/libMagickWand-6.Q16.a /usr/local/lib/libMagickWand-6.Q16.la /usr/local/lib/libMagickWand-6.Q16.so /usr/local/lib/libMagickWand-6.Q16.so.2 /usr/local/lib/libMagickWand-6.Q16.so.2.0.0 Eventhough there's no QBIT, compiling libdmtx obviously fails.
Over to maintainer.
This was just fixed in http://svnweb.freebsd.org/ports/head/graphics/libdmtx/Makefile?r1=359068&r2=359067&pathrev=359068.