The VFS xoroshiro plugin provides a PRNG based on the Xoroshiro12+
algorithm. It is seeded initially and reseeded regularly after a fixed
amount of bytes, around 1 MiB, were produced by reading a seed file.

The plugin supports the following configuration options:

* :name: sets the file-name under which the plugins exposes itself
         to the VFS, the default is 'xoroshiro'.

* :seed_path: specifies the file in the VFS that is read to reseed
              the PRNG.

The following examplary config snippets illustrates its usage:

! <vfs>
!   <dir name="dev">
!     <jitterentropy name="entropy"/>
!     <xoroshiro     name="random" seed_path="/dev/entropy"/>
!   </dir>
! </vfs>
