The grafted replacement of libtiff, libtiff/fixed, updates the package from version 4.1.0 to 4.2.0.
However, the it does not adjust the #:configure-flags of the inherited package, which rely on the version number. The result is directories named 'share/doc/libtiff-4.1.0' in the "doc" output of libtiff-4.2.0.
