patch- depends on libversion

[Martin Klaffenboeck]

Hello,

I'm using libgnomecanvas-2.300 here, so I have to patch gcompris2 (2.1; 
next new port from me) in a file.  for libgnomecanvas-2.200 it is not 
necessary to patch with this file.  So can I use a patch depending on 
the installed version of a lib?  (In this case, I have to tell the port 
to use files/patch-src::boards::menu.c only when gnomecanvas 2.3 is 
installed and not if 2.2 is installed.) Is that possible?

Martin