add zstandard libraries from hdf5plugin for dclab hook

[paulmueller]

The package dclab uses the Zstandard compression algorithm HDF5 plugin from the hdf5plugin package. This pull request makes sure that the corresponding dll/so/dylib files are present in the distribution. I am the author of dclab.
https://github.com/ZellMechanik-Dresden/dclab

[bwoodsend]

Any reason why this should go in the hook for dclab instead of a hook for hdf5plugin?

[paulmueller]

My initial idea was this: If I used a general hook for hdf5plugin, then all of the library files (not only Zstandard) would be added. I intended to only add Zstandard here, because none of the other libraries are required.

But I see that a hook for hdf5plugin might be a better, more general solution, even if it means that it increases the distribution size.

Should I create an hdf5plugin hook instead?

[bwoodsend]

If hdf5plugin is usable without those extra files then no.

[paulmueller]

Then that means yes, because in the most general case, you will need those extra files with hdf5plugin. I will create a hook for hdf5plugin.