Ignore EllipseParam

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>
Prepend (not append) retval

Let's consider varargs at the end of the args.

If we append the retval the type is syntactically wrong.

f(int x, ..., int *retval) NG

Instead we prepend it

f(int *retval, int x, ...) OK

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>