I have some extension code written in C which includes <ruby/dl.h>
The code used some definitions from this file such as "struct ptr_data" and "RPTR_DATA".
The code was working OK with ruby 2.1

<ruby/dl.h> no longer exists in the ruby-2.2.0 source distribution nor the svn trunk.

Is <ruby/dl.h> and all it's definitions now obsolete ? If so is there a proper way
for C extensions to handle arguments which are instances of FFI::Struct ?