Conditional availability of properties

[Tim-Philipp Müller]

On Fri, 2011-09-16 at 21:57 +0200, Stefan Sauer wrote:

> 3.) make it and interface and use GstImplementsInterface (which is on
> the to-kill list for 0.11)

More on the killed-already list. However, I am not sure if you can
convert an existing interface to GstImplementsInterace without some
subtle (or not so subtle) API or ABI breakage somewhere.

 Cheers
  -Tim