Merge branch 'refs/heads/t/portable_io'

A small series with no user-visible impact. After this is merged,
no more casts are necessary for pointers passed to read_u*() and
write_u*() and their big-endian counterparts.

Cooking for five weeks.

* refs/heads/t/portable_io:
  blob: Remove some unnecessary casts for arguments to read_u32().
  crypt: Remove read_ssh_u32().
  Let helpers in portable_io.h receive void * arguments.