hdf5_der

Merge pull request #100 in HDFFV/hdf5 from ~FRANK.WILLMORE/hdf5:HDFFV-8882-replace-numeric-exit-code-with to develop

* commit '526bcc242d03a6fc4fd28d3a0f68cc31f4f2a850':
  Changes to be committed: 	modified:   bittests.c 	modified:   cmpd_dset.c 	modified:   dsets.c 	modified:   dt_arith.c 	modified:   dtypes.c 	modified:   extend.c 	modified:   fillval.c 	modified:   filter_fail.c 	modified:   flush1.c 	modified:   gen_cross.c 	modified:   hyperslab.c 	modified:   istore.c 	modified:   links.c 	modified:   links_env.c 	modified:   objcopy.c 	modified:   plugin.c 	modified:   tcheck_version.c 	modified:   unlink.c 	modified:   unregister.c