Review missing OS support list

[djherbis]

Full list is available here.

Add support for those if possible.

Implementation hints are usually in here in the stat_$OS.go files.

[djherbis]

Missing currently:
android hurd illumos ios zos

None of those have implementation hints in Go std lib afaik, will maybe need some manual digging to find if they have stat commands, and how they should be called / how to test them.

[djherbis]

We also are limited in testing to those envs which TravisCI supports.