hdf5_chunking_query_bmr

[svn-r25667] HDFFV-8933:
Did not provide default values for clang++ options.
Also, applied wrong values for the *_CPPFLAGS.

Solution:
Added default values for *_CXXFLAGS.
Fixed the *_CPPFLAGS values.

Tested: duck, swallow, quail with --eanble-production.