Document OS compatibility

[ndmitchell]

Does this work on Windows? An immediate question for someone coming to the project, and I couldn't tell. My guess is no, as it has an unconditional dependency on unix? Does it work on mac?

[nh2]

@ndmitchell The simple answer is that I don't know.

Like strace, all of hatrace is built around the ptrace() syscall.

• WSL seems to have some support for ptrace; I conclude that from this issue PTRACE_SEIZE not supported microsoft/WSL#3031 where people complain that certain ptrace flags aren't supported, so I suspect ptrace in general is available. Would it working in WSL be useful for you?
• OSX seems to have some ptrace support as per Wikipedia. There is a man page and also http://www.hexblog.com/?p=81 and https://www.spaceflint.com/?p=150. People seem to complain about "lacking documentation".

I have only tested hatrace and strace on Linux.

If WSL is sufficient for you, would you be up for checking what ptrace flags or features it supports? Then I could tell you how well hatrace is supposed to work there.

[ndmitchell]

Unfortunately I don't have WSL installed. Would be interesting to see at least some of this information in the README.

[kirelagin]

Here is a data point:

It doesn’t build on macOS because of SIGPOLL.