HDF5 ==== The `itkhdf5` subdirectory contains a reduced distribution of the hdf5 source tree with only the library source code and [CMake] build system. It is not a submodule; the actual content is part of our source tree and changes can be made and committed directly. Update hdf5 from upstream using the `UpdateFromUpstream.sh` script one directory up. Finally, update symbol mangling according to the instructions in `itk_hdf5_mangle.h`. [CMake]: https://cmake.org/