change git paths to always be / separated

[pfitzseb]

fixes #28.

The LibGit2.isdirty test always succeeds for some reason, even though it should be calling git_diff_tree_to_workdir_with_index which should be diffing the index against the working directory... Should maybe wrap git_diff_index_to_workdir or figure out why isdirty behaves the way it does.

[tkelman]

looks like it needs a url (github username in the config maybe?)

[tkelman]

ref #58 (diff) it would probably be better to set HOME to somewhere temporary for this as part of temp_pkg_dir rather than doing things differently on CI

[pfitzseb]

I tried

    const tmphomedir = mktempdir()

    withenv("HOME" => tmphomedir, "JULIA_PKGDIR" => tmpdir) do
        info("setting git global configuration")
        run(`git config --global user.name "Julia Test"`)
        run(`git config --global user.email [email protected]`)
        run(`git config --global github.user JuliaTest`)

        @test !isdir(Pkg.dir())
        try
            Pkg.init()
            @test isdir(Pkg.dir())
            Pkg.resolve()

            fn(Pkg.Dir.path())
        finally
            remove_tmp_dir && (rm(tmpdir, recursive=true); rm(tmphomedir, recursive=true))
        end
    end

in temp_pkg_dir(), but that doesn't work because

withenv("HOME" => mktempdir()) do
  run(`git config --global github.user JuliaTest`)
  LibGit2.getconfig("github.user", "")
end

doesn't return JuliaTest for some reason... Not sure what's going on there -- maybe HOME isn't properly passed on to libgit2?

[tkelman]

hm. i wonder whether that's an issue in the c library or something our bindings have control over