Add `PKG_EVENT_SANDBOX_GET_STRING` event.
Fix race condition in lock upgrade.
Use int64 type for certlen and siglen.
Add loading of certs from meta in sandboxed mode.
Null terminate string read.
Add utility to extract key from meta in sandbox.
Check meta signature.
Set allocated flag for signature key.
Get pubkey from meta if possible.
Verify signatures inside sandbox.
Include config header where needed.
Fix capsicum mode entering.
Add notice about `rsa_verify` deprecation.
Merge branch 'sandboxed-sig-verify'
- show available space without reservation fact.
- show output units in megabytes rather than gigabytes.
Merge pull request #780 from andrejzverev/master

Calculate available space without reservation.
Change `f_avai` -> `f_avail`.
Sync pkg.conf.5 with the list of config variables in pkg_config.c

Sort into alphabetical order.

Fix some of the descriptive text in pkg_config.c

Fixes: #756
Merge branch 'master' of github.com:freebsd/pkg