No way to have global diff settings? (global .gitattributes feature request)

Hello,

it seems there is no global .gitattribute equivalent to .gitignore or
.gitconfig. Wouldn't it make much sense to have one? Failing that, there
really should be a way to specify some global diff options at least.

My use case:

I wanted to specify something like -F "^(" to git diff for lisp files.
But well, git diff has no -F option! So shruggar from #git pointed me to
gitattributes. OK, that's great and works, but now I have to put
.gitattributes or info/attributes to all repos with lisp files in them?
That rather sucks, if you ask me.

So I would like to ask if there is a way, and if not, if it could be
considered a useful feature addition.

Thanks,

  Štěpán