Log Message:
Update devel/hdf5 from 1.6.10nb1 to 1.8.7.

A list of changes is available at

http://www.hdfgroup.org/HDF5/doc/ADGuide/Changes.html

A list of new features of 1.8.x release is available at

http://www.hdfgroup.uiuc.edu/HDF5/doc_1.8pre/WhatsNew180.html

This update removes "cxx" option from the package. New devel/hdf5-c++
should be used instead.