This is a portable C FFI for Lua, based on `libffi` and aiming to be mostly
compatible with LuaJIT FFI, but written from scratch. Compatibility is
preserved where reasonable, but not where not easily implementable (e.g.
the parser extensions for 64-bit `cdata` and so on). Thanks to `libffi`,
it works on many operating systems and CPU architectures. The `cffi-lua`
codebase itself does not contain any non-portable code (with the exception
of things such as Windows calling convention handling on x86, and some
adjustments for big endian architectures).
