[Libguestfs] [PATCH nbdkit v2 0/4] common/allocators: Always align mlock buffer

Earlier patch was reviewed here: https://listman.redhat.com/archives/libguestfs/2022-January/msg00172.html For this series I pulled out two smaller changes into separate commits (patches 1 & 2). I then decided to modify the vector library to add a new <vector>_reserve_page_aligned function which always allocates page-aligned memory (patch 3). Currently this is using posix_memalign, maybe in future using mmap since there seems to be some dispute about whether calling mlock on anonymous memory is safe. This makes the change to common/allocators/malloc.c quite straightforward (patch 4), at the cost of making the change to the vector library rather headache-inducing. At least it is confined to a new function and doesn't affect any existing callers! Rich.