Useful systemwide git defaults -- revisited

A while back, I wrote about “useful git defaults”. This is a tricky subject, as a sufficiently aged ~/.gitconfig is much like a vimrc or Chief O’Brien’s rank: a very religious topic. Nonetheless, it’s one of those things where a few small adjustments to the system-wide git configuration (a la /etc/gitconfig) can make things much, much easier — particularly in the case where there are multiple systems to manage, and multiple people using them.