If it were me, I would simply choose a different name.

OS/X after-all is not the only well-known operating system out there with a case-preserving but case-insensitive file system! So, if you find yourself in any situation that could be adversely affected by name-clashes of this sort, in the long run you're going to have to resolve that problem ... not by “redefining the file system” (especially not when that will undoubtedly break everything-else in that world), but by changing the nature of your application.

Perl obviously doesn't require a case-sensitive filesystem. It operates quite happily in either situation and contains a plethora of good CPAN modules for dealing with such OS-dependent issues.

Apps simply cannot waltz in and sing, “change your world for me-e-e-e...” Nor can a developer claim sufficiency just because “it works on my box.” The app needs to use CPAN-modules (and built-in File modules) that know how to “behave appropriately.” By delegating the action to an external package that, for all you know (but do not care) might well be environment-dependent, the application becomes environment-independent.