for encryption, aws s3 provides an "encryption" context to vary per-object
keys. The encryption context is a base64 encoded json structure, which
must be converted to a determinstic form -- "canonical json". This
requires converting all strings to a normalized canonical form: "utf-8 nfc",
it also requires thta keys in objects be sorted in a fixed order; so some
form of sorting based on nfc.
It turns out that libicu was the best way to produce utf-8 nfc (boost also
provides a mechanism, but it has many quirks). So, here are the hooks
to pull the system libicu into the build.
Fixes: http://tracker.ceph.com/issues/48746
Signed-off-by: Marcus Watts <mwatts@redhat.com>
