clear cache

[Michael Grunditz]

> I remember that we encountered the same problem recently in the context
> of the Javascript JIT compiler of the Chromium engine [1]. Since there
> exists no POSIX API for the instruction-cache invalidation, we decided
> to add a new public interface to the libc [2].
>
> [1] https://github.com/genodelabs/genode/issues/3858
> [2]
> https://github.com/genodelabs/genode/blob/master/repos/libports/include/libc/genode.h

Wow , thanks. My code runs 10x faster now.
I have a lot of optimisations to do, but happy so far.

Michael