zeromq/libzmq — pull request #696 by calid (2013-10-04 07:08:41+00:00)
Title: replace macro constants with enum types for user facing constants

Mentioned this to Pieter in IRC, and here is the patch. Results in clearer compiler errors/warnings, and interfaces better with debuggers and analysis tools. From a functionality perspective there should be no impact (and I got no test failures).