Best practices for cross platform git config?

Solution 1:

Never turn autocrlf on, it causes nothing but headaches and sorrows.

There's no excuse to use \r\n on windows, all decent editors (by definition) can handle \n.

Solution 2:

I have reviewed that kind of config setting (crlf) extensively in the question:
distributing git configuration with the code.

The conclusion was:

• checkout/checking .gitattributes files
• list all types which explicitly need that kind of conversion.
  For instance:

*.java +crlf
*.txt +crlf
...

• avoid doing any kind of conversion of type of files which don't need it, because of the various side-effect of such a conversion on merges, git status, shell environment and svn import (see "distributing git configuration with the code" for links and references).
• avoid any crlf conversion altogether if you can.

Now, regarding the specific issue of per-platform settings, branch is not always the right tool, especially for non-program related data (i.e; those settings are not related to what you are developing, only to the VCS storing the history of your development)

As stated in the question Git: How to maintain two branches of a project and merge only shared data?:

your life will be vastly simpler if you put the system-dependent code in different directories and deal with the cross-platform dependencies in the build system (Makefiles or whatever you use).

In this case, while branches could be use for system-dependent code, I would recommend directory for support tools system-dependent settings, with a script able to build the appropriate .gitattributes file to apply the right setting depending on the repo deployment platform.