Rebase

This page lists actions that xemul@ needs not to forget when doing rebase after next release.

• Add UFFD mark to 'criu: a few fixes to build on Alpine'
• 'crtools.h: Drop protobuf.h inclusion' is now 'uffd: Include protobuf'
• 'crtools.h: Move prepare_task_entries from it' is now for uffd
• 'mem: Move mem_pp from ctl to pstree_item's dmpi' is now uffd only
• 'page-read: fix open_page_read usage' is uffd only