Hard-coded default path to man-pages

[stv0g]

By @koraa in #27 (comment)

https://github.com/stv0g/go-rosenpass/blob/d7e38ecaf9e7803f2824a03ac24ac34944a53af6/cmd/main.go#L104

Severity: A (Functionality) – Path to man pages hard coded (will be incompatible with installing as a system package)

[stv0g]

The hard-coded path is in fact just a default value and can be overwritten by the user via a CLI flag.

Determining a suitable install location for the generated man-pages is actually not so easy as its itself configurable via /etc/manpath.config or ~/.manpath.

See:

• manpath(1)
• /etc/manpath.config

I am open to change the behaviour, if we can find a better way to identify a good man-page install location.

(/usr/local/share/man/man1 should be standardized by the FHS)