re: github issue https://github.com/Unidata/netcdf-fortran/issues/82
This was originally discovered in the Fortran tests, but is
a problem in the C library.
The problem only occurred when using HDF5-1.10.x. The reason it
failed is that starting with 1.10, the hid_t type was changed
from 32 bits to 64 bits.
The function libsrc4/nc4memcb.c#NC4_image_init was using type int (doh!)
to return the hdf fileid instead of hid_t type. This, of course,
caused the id to be truncated and in turn later use of the id
caused hdf5 to fail.
Fix is trivial: replace int with hid_t. This also requires a related
change in nc4mem.c.
Also added the test case derived from the original Fortran code.
You would think I would learn...
