[polyml] Version 5.8.1 Release

On 21/07/2020 12:30, Makarius wrote:

Rather soon, I will continue on the Isabelle repository with Poly/ML repository versions, because I want to start using the experimental GCPercent feature. (The next Isabelle release will probably be in Jan-2021.)

I've updated the GCPercent branch to incorporate 5.8.1.

For everyone else: the GCPercent branch adds information to the statistics about operations, primarily garbage-collection, that may cause ML to be unresponsive for significant amounts of time. It requires a separate process to read the statistics since obviously the local ML code can't. It's rather experimental at the moment which is why it's not yet in the main line.

David