Build Emacs on Appveyor

[TheBB]

This adds an emacs-appveyor.mk that is the spiritual complement of emacs-travis.mk. It doesn't have all the bells and whistles of the latter though, I just tore out the things I didn't need and made sure it worked for our use cases.

This PR also disables CI for 25.1 and 25.2. They take a while to run and presumably 25.3 should suffice for the 25.x line.

This should bring Windows CI up to par with Linux and OSX.

[TheBB]

Wonderful, now Travis is broken.

@vermiculus Do we need to ensure that $(HOME)/bin exists before flycheck/emacs-travis@1113a8e#diff-f77d2e20db9b107bbe7ad78eba678f65R150 ?

[vermiculus]

I'll see how I can help with Travis when I'm free again :-)
We probably should be, but does that impact this build? I don't see a call to ln.

[TheBB]

Sure, take your time ;-)

It fails on all OSX builds here: https://travis-ci.org/magit/libegit2/jobs/388730159#L5420, which corresponds to the line I linked above.

[tarsius]

Should we ask for help with this and #6 on the reddit thread too?

[vermiculus]

I've been working on the macOS build over at flycheck/emacs-travis#19. It only seems to fail for Emacs 26+; not really sure what's going on yet.

[vermiculus]

Update on the above: the macos build should work now. don't know why it was broken in the first place; I would just try restarting the build from travis.

[vermiculus]

Looks like the build is still failing. I'll look into it when I'm home in a few hours.

[vermiculus]

It might be this project's own Makefile as opposed to emacs-travis.mk.

[TheBB]

No I'm pretty sure it's the symlink in emacs-travis.mk. Maybe it'd be simpler just to ln -sf.

[vermiculus]

I don't think so, but I can confirm when I'm home. What makes me think so is that emacs-travis's own tests are passing for this configuration and the steps right before the failure and the reported target correspond to the emacs target in this Makefile:

https://github.com/magit/libegit2/blob/b5e4e5e591f27dd6bea3a79d8b41bcbc2f5f06ad/Makefile#L35-L44

I might try basing this Makefile off the emake example repo -- that build seems to work (and there have been a few enhancements made since this was first implemented).

[vermiculus]

I don't think I have push access to this branch (which makes sense as I don't have push access to the repo in general), so here's configuration that may work:

https://gist.github.com/vermiculus/74f3396779f05b6c2e8a6daaaf88031b

[TheBB]

@vermiculus I've added you as a collaborator to my fork, should give you push access to this branch.

[TheBB]

Looks pretty good!