git add to ignore whitespaces, some day?

Hey,

It would be nice if git-add could be told to ignore whitespace changes, wouldn't it?

According to SO, I am not the one to think so: http://stackoverflow.com/questions/3515597/git-add-only-non-whitespace-changes

A change to add--interactive would be as simple as adding the diff -b or -w option like: my @diff = run_cmd_pipe("git", @diff_cmd, "-w", "--", $path);

But I wonder if this should be configured in a diff.ignorews or passed as an argument to git add. Opinions?