Adding them seems trivial because generic versions are supposed to work, but 'make makepatch' fails to recreate patches for this port, so I couldn't generate a patch in a usual way.
I reported this at the valgrind site:
I was told to report it here by them. Apparently this is a duplicate.
Maintainership dropped ports r495096.
Assign to new maintainer.
I've added these syscalls in my github repo