And those on Mac should be able to use:
$ brew install c
And those on Mac should be able to use:
$ brew install c
Even so, based on the general rules for homebrew inclusion they would reject the formula because:
1. I don't think they like names that have the potential to conflict with others ("c" is in that category). The shortest name I see in their repo is two chars.
2. Typically they only want widely used formulas ("We generally frown on authors submitting their own work unless it is suitably notable." [1]).
[1] https://github.com/mxcl/homebrew/wiki/Acceptable-Formula
Also, it is only my hunch that they wouldn't accept the formula--you can still try. I'd still rename the project to be more descriptive (dir-c?) as there are only two homebrew formulae that have single char names (R, which has been around since 1993 and Z, which I'm surprised got included).