s390/s390-64 missing xattr exports

[Andreas Jaeger]

Ok, I'll work on adding all this stuff now:
- Add the xattr interface for all architectures with ENOSYS stubs in
  sysdeps/generic
- adding a sys/xattr.h header, this one should go into
  misc/sys/xattr.h.
- Reverting the patch for Versions that added those to some Linux
  archs
- and instead add a patch to misc/Versions with the new symbols.

Is this ok?
Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj