tiff: build tiff2ps and tiff2pdf

[tornaria]

Testing the changes

• I tested the changes in this PR: briefly

These two very useful tools were declared "unsupported" in the current version of tiff (4.6.0, sep 2023).

See: http://www.simplesystems.org/libtiff/releases/v4.6.0.html#tools-changes

[cinerea0]

Given that upstream has directly stated these tools are unsupported it may be a better idea to move building them behind a non-default build option instead of enabling them for everyone.

[sgn]

I think those tools would be built by tiff5 package instead, no?

[sgn]

So, anything unsupported stay with unsupported tiff

[tornaria]

Here's one attempt. I'm not sure I have the conflicts= line right.

OTOH, I wonder if, even if tiff2ps and tiff2pdf are "unsupported" in tiff 4.6.0. Is it better to build them from tiff 4.4.0 (linked to old libtiff) or build them from tiff 4.6.0 (linked to new libtiff).

Moreover, it seems that tiff5 is only kept to support a nonfree / binary only package wps-office so it might be dropped at some point.

So, here's an alternative proposal: use --enable-tools-unsupported, but move the unsupported tools (tiff2ps and tiff2pdf) to a separate package tiff-unsupported.

Note that upstream differentiates between "unsupported" tools (tiff2ps and tiff2pdf) which are "easy" to build via a configure switch, and "archived" tools (fax2ps, ...) which are not built with a configure switch if I'm not mistaken. See: https://gitlab.com/libtiff/libtiff/-/merge_requests/520.

I can implement the alternative proposal if you agree with it.

[tornaria]

Here's the second attempt: this adds a subpkg tiff-unsupported which contains the two unsupported tools (which upstream still ships the source in the tarball, even if they don't build or install them by default). I added the man pages from tiff-4.5.1 since they are not in the tarball.