no longer bundle libzmq as DLL

tools/test_wheel.py

@@ -56,6 +56,3 @@ def test_bundle_msvcp():
 
     for dll in should_bundle:
         assert dll in dlls
-
-    assert any(dll.startswith("libzmq") for dll in dlls)
-    assert any(dll.startswith("libsodium") for dll in dlls)

zmq/__init__.py

@@ -3,64 +3,11 @@
 # Copyright (C) PyZMQ Developers
 # Distributed under the terms of the Modified BSD License.
 
-# load bundled libzmq, if there is one:
-
 import os
 import sys
 from contextlib import contextmanager
 
 
-def _load_libzmq():
-    """load bundled libzmq if there is one"""
-    import platform
-
-    dlopen = hasattr(sys, 'getdlopenflags')  # unix-only
-    # RTLD flags are added to os in Python 3
-    # get values from os because ctypes values are WRONG on pypy
-    PYPY = platform.python_implementation().lower() == 'pypy'
-
-    if dlopen:
-        import ctypes
-
-        dlflags = sys.getdlopenflags()
-        # set RTLD_GLOBAL, unset RTLD_LOCAL
-        flags = ctypes.RTLD_GLOBAL | dlflags
-        # ctypes.RTLD_LOCAL is 0 on pypy, which is *wrong*
-        flags &= ~getattr(os, 'RTLD_LOCAL', 4)
-        # pypy on darwin needs RTLD_LAZY for some reason
-        if PYPY and sys.platform == 'darwin':
-            flags |= getattr(os, 'RTLD_LAZY', 1)
-            flags &= ~getattr(os, 'RTLD_NOW', 2)
-        sys.setdlopenflags(flags)
-    try:
-        from . import libzmq
-    except ImportError:
-        # raise on failure to load if libzmq is present
-        from importlib.util import find_spec
-
-        if find_spec(".libzmq", "zmq"):
-            # found libzmq, but failed to load it!
-            # raise instead of silently moving on
-            raise
-    else:
-        # store libzmq as zmq._libzmq for backward-compat
-        globals()['_libzmq'] = libzmq
-        if PYPY:
-            # should already have been imported above, so reimporting is as cheap as checking
-            import ctypes
-
-            # some versions of pypy (5.3 < ? < 5.8) needs explicit CDLL load for some reason,
-            # otherwise symbols won't be globally available
-            # do this unconditionally because it should be harmless (?)
-            ctypes.CDLL(libzmq.__file__, ctypes.RTLD_GLOBAL)
-    finally:
-        if dlopen:
-            sys.setdlopenflags(dlflags)
-
-
-_load_libzmq()
-
-
 @contextmanager
 def _libs_on_path():
     """context manager for libs directory on $PATH