Darwin platform support

[LEI]

First of all while attempting to use jobber on macOS Sierra, I had to create common/su_cmd_darwin.go for it to compile successfully (osx man su almost matches freebsd).

Then after some more fiddling I realised jobbermaster couldn't properly list users since Apple's /etc/passwd does not contain this information. It would require an alternative listUsers method for GOOS=darwin.

By the way you might be aware of this but Go build constraints are useful for cross-platform programs, maybe it's worth integrating in the build system (if not already?).

Are you planning to fully support this OS, or are there too many other corner cases?
I would gladly help however I can, may it be contributing or testing.

Also as addressed in #200, running rootless would be nice.

[LEI]

Just stumbled upon #67: if jobber can run on macOS after some modifications, one could package it with Homebrew and leverage its services to daemonize the program. Almost all files installed with brew live under /usr/local to allow non-root execution.

[dshearer]

Okiedokie, I’ll look into it.

…

On Jul 23, 2018, at 1:33 PM, Guillaume ***@***.***> wrote: Just stumbled upon #67: if jobber can run on macOS after some modifications, one could package it with Homebrew and leverage its services to daemonize the program. Almost all files installed with brew live under /usr/local to allow non-root execution. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[LEI]

The most reliable way seems to be dscl . list /Users | grep -v '^_' which outputs something like:

daemon
Guest
User1
nobody
root

For now I added an alternative listUsers function in jobbermaster/users_darwin.go.

[johnson7788]

Hi bigman
is it support Mac now?

[dshearer]

Not yet. I'll add it in next release.

[dshearer]

Pr #220

[johnson7788]

Perfect job!

[dshearer]

Don't know why this is still open. It was done in 1.4.