Squashed 'src/zeromq/' content from commit 86c1e83

git-subtree-dir: src/zeromq
git-subtree-split: 86c1e83e3f28a59c5d09273bd5234d96cbc0d60b
Merge commit 'd1000795c3066b6c63de545aededfcbeae08fe89' as 'src/zeromq'