Bug report: $program_name in error message

To reproduce, run 'git submodule' from within a bare repo. Result:

$ git submodule fatal: $program_name cannot be used without a working tree.

Looks like the intent was for $program_name to be interpolated.

As an aside, I sent a message a few days ago about a segfault when working with a filesystem with direct_io on, but it appears not to have made it to the archives on marc.info. Am I perhaps still greylisted?

Thanks, Josh