Delegating part of a job to a slave is something that would have to be done external to Jenkins, for example, using ssh.
However, as @kan indicates, you most likely want to extract the native library build as a separate job and then have that job execute on a particular slave, or any slave that meets a specific criteria.
To do this, my suggestion would be to use Labels in the node configurations to determine which slaves can be used for building that particular job.
In Jenkins > nodes > <slave node>, use the Labels property to set one-word labels that indicate your specific requirements, such as the OS or processor type.
Then, in the jobs that are node-specific, check Restrict where this project can be run and set the Label Expression to something that meets your criteria. If the criteria is simple, it will just be a single word, if you need a boolean, you can use those as well (such as OSX&&Lion in our case).
I believe this is all in the standard version of Jenkins, without need for a special plugin. Leave me a comment if it isn't and I'll try and diagnose which plugin enables this functionality.
