1 fix and 2 small changes for worley

The lack of parens around *delta in worley.h compared to worley.c actually prevent it from being compiled by gcc.

The other change was to remove the #pragma once from worley.h (gcc enables this by default, and there are guard macros anyhow) and to add a (admittedly gcc specific makefile).

Consider accepting the first change in any case.

If you prefer me to send you patches rather than a pull request, I can do that.

Thanks,

-- steve