This function exempts an ObjectObject pointer from AST context
handling, as implemented by astBeginastBegin and astEndastEnd. This means that
the pointer will not be affected when astEnd is invoked and will
remain active until the end of the program, or until explicitly
annulled using astAnnulastAnnul.
If possible, you should avoid using this function when writing
applications. It is provided mainly for developers of other
libraries, who may wish to retain references to AST Objects in
internal data structures, and who therefore need to avoid the
effects of astBegin and astEnd.