Mk/bsd.port.mk: move WWW to Makefile

[se]

Summary

Support WWW variable in Makefile instead of the pkg-descr file.

This patch is based on review D34979 by @tcberner but with 2 noticeable changes:

• The www-site target is preserved and just returns the value of the WWW variable.
• The create-manifest script appends the value of the WWW variable to the copy of the pkg-descr file in the manifest.

Both these extensions of the patch in D34979 are meant to preserve previous behavior in case some 3rd party script depends on the target or structure of the pkg-descr file.

This patch-set should not be applied before there are WWW values in all port Makefiles.
The WWW variables in port Makefiles depend on updates of the portlint and portfmt ports (sent to the respective maintainers) to be committed to the ports tree.

Test Plan

Apply patch and verify the following features:

• The WWW variable is passed into the output of "make describe" (used to build the INDEX).
• The WWW variable is passed into the manifest of generated packages.
• The WWW variable is appended to the contents of the pkg-descr file in the "desc" element of the manifest in generated packages.

[tcberner]

[dvl]

Will this be MFC into the latest quarterly branch? I'm going to guess know.

The answer affects FreshPorts changes to cater for make -V WWW - if that won't work on quarterly branches until 2022Q4, I will delay the changes until then.

[se]

In D36434#829295, @dvl wrote:

Will this be MFC into the latest quarterly branch? I'm going to guess know.

The answer affects FreshPorts changes to cater for make -V WWW - if that won't work on quarterly branches until 2022Q4, I will delay the changes until then.

The patch took care that there still is a WWW: line at the end of the package description in the manifest.

If FreshPorts extracts the "desc" element from +MANIFEST, then no change should be required and the WWW field in the Makefile (and the www element in the manifest) could be ignored.

I had no plans to merge these changes to the existing quarterly branch, wanted to just have them appear in the next quarterly branch after small issues with this patch have been fixed in the main branch.

Please send mail to se@ if you want to discuss any details - I'm willing to work out whatever it takes to make this change smooth for FreshPorts.