Merging in latest from upstream (HDFFV/hdf5:refs/heads/hdf5_1_12)
* commit '1097ac60c2b95a2b958a3150b537c75f512cacca':
Merge t_2Gio test into hdf5_1_12. This will eventually be refactored out after merging the test functionality into the testphdf5 test.
Merge t_2Gio test into hdf5_1_12. This will eventually be refactored out after merging the test functionality into the testphdf5 test.
Minor tweaks noticed while going over VOL documentation.
Yanked -Wc++-compat from the flags used to build the C library in both the Autotools and CMake.
Fixed missing blob callbacks in test VOL connectors.
Trivial parameter renaming in VOL API calls.