Fix LIBZMQ-576 - Revert "Merge pull request #76 from hintjens/master"

This reverts commit a0a24a92af78ebb8f61a8a45454d3ff6d2db0a3d, reversing
changes made to 8e748064acf877e5322f681c30323d7dc91e2100.

See https://zeromq.jira.com/browse/LIBZMQ-576 for details