FastCGI over Unix socket

[clarfonthey]

• Gitea version (or commit ref): Gitea version 1.9.3 built with go1.13.1
• Git version: git version 2.23.0
• Operating system: OpenBSD 6.6 GENERIC.MP#0 amd64

Description

Right now, setting PROTOCOL = fcgi allows FCGI over TCP only, which is a bit odd, considering how FastCGI is something that's usually only run locally. If HTTP_ADDR is set to a path for a unix socket, Gitea will error stating that the address is unknown (because it's not actually a hostname).

Because OpenBSD's httpd does not allow full HTTP proxying and only FastCGI, using a unix socket is not possible with this configuration.

This would be a breaking change, but I would personally recommend renaming the unix protocol to unix+http and adding an additional unix+fcgi protocol as well.

Ideally, using the unix protocol without specifying which would emit a warning.

[zeripath]

I think it would be easiest just to use fcgi+unix - then this doesn't need to be a breaking change.