Merging in latest from upstream (HDFFV/hdf5:refs/heads/hdf5_1_10)
* commit 'd6ea49f5cbcaa852cd0caf34278ec61108667bc3':
Switch to using flag in signal handler, to trigger dropping out of main loop and shutdown cleanly, instead of calling leave() from the signal handler.
Fix HDFFV-8089 Description: Some code within an "ifdef H5D_CHUNK_DEBUG" block was using outdated data structure but not caught because the case of H5D_CHUNK_DEBUG being defined was never tested. It was commented out. I defined H5D_CHUNK_DEBUG, tested, and commented out again. Platforms tested: Linux/32 2.6 (jam) Linux/64 (platypus) Darwin (osx1010test)
