Typedefs for pointers to opaque structs

[dmlary]

A typedef for a pointer to an opaque struct results in invalid ruby being generated.

Given the following C code:

typedef struct opaque_struct* opaque_pointer;
opaque_pointer func(void);

ffi-swig-generator outputs the following ruby:

attach_function :func, :func, [  ], :opaque_pointer

The line defining the :opaque_pointer as a :pointer is missing. The output should be as follows:

typedef :pointer, :opaque_pointer
attach_function :func, :func, [  ], :opaque_pointer