Never say die: compiling the git manual on OSX

Last night I battled with my computer trying to get git's manual to install. Yes, I know they distribute the manual already packaged, but I have my git compiled from their repo, so why shouldn't my docs be in step? I found a lot of info on this wiki page that helped get me started in the right direction, but was still having issues. Turns out, the latest version of xmlto uses a cp -a command which is a no-go on OSX.

The fix is simple enough, on line 11 of format/docbook/man, change "cp -a -- ..." to "cp -- ..." and you're done.