No longer bundle libzmq with IPC support

due to bugs that cause crashes that can't be worked around

wait for at least 4.3.5 before re-enabling

buildutils/bundle.py

@@ -44,12 +44,19 @@
 ROOT = os.path.dirname(HERE)
 
 
+# msvc 142 builds have a problem:
+# on _some_ (unclear which!) systems due to the implementation of runtime detection of AF_UNIX
+# in 4.3.4
+vcversion = 141
+# until that's fixed, we shouldn't ship 142 builds,
+# which in turn means we can't support IPC in wheels
+
 if platform.architecture()[0] == '64bit':
     msarch = '-x64'
-    vcversion = 142
+    # vcversion = 142
 else:
     msarch = ''
-    vcversion = 141
+    # vcversion = 141
 
 libzmq_dll = f"libzmq-v{vcversion}{msarch}-{x}_{y}_{z}.zip"
 libzmq_dll_url = f"{download_url}/{libzmq_dll}"