The package intentionally does not build a shared library for libhsclient.

This is primarily because it is unclear if upstream is prepared to start
versioning the library appropriately. Until then, libhsclient-dev can only
be statically linked to.

See this issue for any response:

https://github.com/ahiguti/HandlerSocket-Plugin-for-MySQL/issues/issue/36

Also the program 'hsclient' is excluded intentionally because it lacks any
form of documentation.
