I am using the ssh-agent that comes with Git for Windows, and it works quite well with ssh itself, but it is not working through packer. Is that known to work and I'm doing it wrong, or is it unsupported, or is it a bug?

When I set PACKER_LOG=1 and run the build with -debug, the error I see is:

[ERROR] "could not connect to local agent socket: /tmp/ssh-xxxxxxxxx/agent.pid"

Looking at the code, I can see that message is generated here.

Packer Version: 0.10.1
Host Platform: Windows 7