explicitly set rpath for zlib otherwise dmtx-utils might be linked to system zlib.

component/libdmtx/buildout.cfg

@@ -5,6 +5,7 @@
 extends =
   ../imagemagick/buildout.cfg
   ../jbigkit/buildout.cfg
+  ../zlib/buildout.cfg
 parts =
   libdmtx
   dmtx-utils
@@ -26,4 +27,4 @@ environment =
   PATH=${pkgconfig:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${imagemagick:location}/lib/pkgconfig:${libdmtx:location}/lib/pkgconfig
   CPPFLAGS=-I${libdmtx:location}/include
-  LDFLAGS=-Wl,-rpath=${jbigkit:location}/lib
+  LDFLAGS=-Wl,-rpath=${jbigkit:location}/lib -Wl,-rpath=${zlib:location}/lib