hdf5_der

Merge pull request #381 in HDFFV/hdf5 from ~LRKNOX/hdf5_lrk:hdf5_1_10_1 to hdf5_1_10_1

* commit 'dd965e4b1498003a2a15d03afdc7e8049d61a5c0':
  Changing default build mode in configure.ac requires running autogen.sh to propagate the change to configure.