Log Message:
graphics/tiff: Update to 4.6.0

Following upstream guidance, tools that are no longer supported are
not built by the package.  As raised on tech-pkg on October 2, with no
objections or even comments.

Upstream NEWS content:

This version removes a big number of utilities that have suffered from
lack of maintenance over the years and were the source of various
reported security issues. See "Removed functionality" below for the
list of removed utilities. Starting with libtiff v4.6.0, the source
code for most TIFF tools (except tiffinfo, tiffdump, tiffcp and
tiffset) was discontinued, due to the lack of contributors able to
address reported security issues. tiff2ps and tiff2pdf source code has
been moved in a unsupported category, no longer built by default, but
are still part of the the source distribution. Other retired utilities
are in a archive/ directory, only available in the libtiff git
repository. Issues related to unsupported and archived tools will no
longer be accepted in the libtiff bug tracker.

The usual bugfixes.