We don't currently have a way to rebuild xhpast.exe (a contributor who isn't very active anymore was maintaining it), and xhpast has updated since then, so there's no easy option here. Some possible options are:

• Figure out how to rebuild xhpast.exe yourself (D3950, D3824). It looks he was able to build it under mingw without much difficulty. This is probably the best approach, and we'd be happy to upstream it. If you figure this out and can walk me through it, I can get this building in the upstream going forward.
• Change the expected version number in the source to match the last version of xhpast.exe, which will let the existing xhpast.exe run. We haven't made any huge updates since then, just some minor fixes.
• T1534 / D3289 started exposing this over Conduit so you wouldn't need a local copy of xhpast.exe, but we got a build before completing that work. Given the relative ease of producing a build and the messiness of using Conduit, I'd prefer not to pursue this option.
• Generally, developing Phabricator itself (and using some of the developer tools) under Windows enjoys less support than on OSX/Linux. It's definitely possible, but currently the entire core team is OSX or Linux.

Thanks.

I will see what I can manage and get back to you if I have any luck!!

Edit: the version of the xhpast I have is 0.62 which I believe is the same needed. (I did not change anything in the source). So, in theory something should work right?

I will try and see if the mingw approach works.

I got something a bit better.

Installed mingw. Then using it nagivated to Phabricator\libphutil\support\xhpast and ran make; make install. That built xhpast correctly and now arc liberate does not complain.

Ah, nice! That sounds pretty easy. I'll see if I can do the same and get an upstream build.

Thanks.

I will get back at you if I come up with a better solution.