I've added a .png file to my repo, for an architecture diagram.
Unfortunately the _verify_lintspaces target tries to run lintspaces on every git recorded file, including the PNG file, which obviously breaks the build.
lintspaces should only run on text files, or restrict to known extensions, rather than on the entire output of git ls-files -z $1 | tr '\0' '\n' | xargs -I {} find {} ! -type l