New master site: sourcehut

[github_evilham.com]

Summary

sourcehut is already a viable alternative to GitHub, with a valid business model and it's entirely open source.
It focuses on power users and tries to simplify workflows for develoepers as much as possible.

It's not unthinkable that more and more projects start using either sr.ht or a self-hosted instance as upstream.

This patch intends to add support for USES_SOURCEHUT and, from my limited testing, it works quite well for custom ports.

Test Plan

Started working on ports with upstream on sr.ht, make makesum works nicely.

[val_packett.cool]

We already have some ports that should be converted to this:

• x11/wshowkeys
• x11/wofi (commented out for now but note hg instead of git site. I guess SRHT_SITE=https://hg.sr.ht would be fine, an additional variable for just the git or hg of the .sr.ht URL would be ridiculous)
• multimedia/wlrobs (same)
• x11/wev
• textproc/scdoc
• mail/aerc

[github_evilham.com]

It somehow didn't cross my mind to check for ports already using sr.ht.

Anyway, I have an idea, how about a USES_SOURCEHUT_HG variable?

• It could be used *instead of* USES_SOURCEHUT for mercurial support
• If it is defined, we default SRHT_SITE to hg.sr.ht, otherwise everything else is the same as in the proposed patch

And followup question: should porting those ports to using this be a different diff?

[github_evilham.com]

Addeed support for USES_SOURCEHUT_HG.

It behaves the same as USES_SOURCEHUT and uses the same variables,
the only change is the default value for SRHT_SITE.

[github_evilham.com]

This is ATM partially blocked by a bug in hg.sr.ht: https://todo.sr.ht/~sircmpwn/hg.sr.ht/33
If someone is interested in helping fix that, feel free to ping me :-).