cppzmq: "ZeroMQ version not supported!"

I have been trying to figure this out for some time now, and I can’t for the life of me.

Steps to reproduce: the ones in the README, to the letter.

tar files: https://github.com/zeromq/libzmq/archive/v4.2.2.tar.gz https://github.com/zeromq/cppzmq/archive/v4.2.2.tar.gz

libzmq builds and install fine. No matter what I do, cppzmq then doesn’t configure:

-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:16 (message):
  ZeroMQ version not supported!

Any tips?