Hello,

GDB screws up the passing of function parameters when the ABI uses a 
descriptor (it passes the code instead of descriptor address). Anyway, 
it's a bug.  This changes the xfail's for that case into kfails 
(refining them a little - powerpc*-*-* is too broad, the tests work on 
some powerpc machines).

I think its almost but not quite obvious so I'll commit it in a day or so,
Andrew