zeromq: make libsodium optional.

Otherwise `ntopng` has issues when linking against them statically.

Closes #33697.
Closes #33677.
zeromq: update 4.0.5_2 bottle.

Closes #33708.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Always set sysroot for Xcode-only systems

Fixes #33431.
Revert "Revert "xcode: use 6.1 on Mavericks.""

This reverts commit 2b472a6e2634a7b7592abb7084b20a098f4a488b.
Update recommended Xcode for 10.9
hamsterdb: add 2.1.8_1 bottle.