Merge branch 'tb/sanitize-decomposed-utf-8-pathname'

Teaches git to normalize pathnames read from readdir(3) and all arguments from the command line into precomposed UTF-8 (assuming that they come as decomposed UTF-8) to work around issues on Mac OS. I think there still are other places that need conversion (e.g. paths that are read from stdin for some commands), but this should be a good first step in the right direction. * tb/sanitize-decomposed-utf-8-pathname: git on Mac OS and precomposed unicode