Document how $HOME is set on Windows

[alejandro5042]

Git documentation refers to $HOME and $XDG_CONFIG_HOME often, but does not specify how or where these values come from on Windows where neither is set by default. The new documentation reflects the behavior of setup_windows_environment() in compat/mingw.c.

[dscho]

Thank you for your contribution!

And sorry for waiting so long to merge it; I meant to communicate more publicly that I was struggling with some issues in the automated build that backs the snapshots; Happily, these issues are sorted out and the next snapshot build will include your changes!

[alejandro5042]

For some reason, when rendered in the help HTML, it doesn't render correctly:

Would you know why?

[nalla]

System
------------

should be

System
------

[alejandro5042]

Thanks @nalla! I proposed PR #1597 to fix the formatting.

[sixcorners]

You mentioned $HOME and $XDG_CONFIG_HOME but this pull request just documents $HOME. What happened to $XDG_CONFIG_HOME?

[alejandro5042]

@sixcorners You're right that this change only documented $HOME (as the title says) and that there still is a documentation gap with $XDG_CONFIG_HOME.

You can find how $XDG_CONFIG_HOME is set here:

https://github.com/git-for-windows/git/blob/master/path.c#L1422

Basically, it falls back on a derivative path of $HOME.

Perhaps you would like to contribute the new section for this variable?

[dscho]

XDG_CONFIG_HOME is not actually set by Git. If set, it is respected. If unset, Git will substitute $HOME/.config whenever it wants to find anything in XDG_CONFIG_HOME.