zipimport.ZipImportError: can't decompress data; zlib not available on macOS

```
Inspect or clean up the working tree at /var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380
Results logged to /var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380.log

Last 10 log lines:
File "/private/var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380/Python-3.7.2/Lib/ensurepip/__main__.py", line 5, in
sys.exit(ensurepip._main())
File "/private/var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380/Python-3.7.2/Lib/ensurepip/__init__.py", line 204, in _main
default_pip=args.default_pip,
File "/private/var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380/Python-3.7.2/Lib/ensurepip/__init__.py", line 117, in _bootstrap
return _run_pip(args + [p[0] for p in _PROJECTS], additional_paths)
File "/private/var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380/Python-3.7.2/Lib/ensurepip/__init__.py", line 27, in _run_pip
import pip._internal
zipimport.ZipImportError: can't decompress data; zlib not available
make: *** [install] Error 1
Exiting due to failure
```

I followed the note but still doesn't work. I'm using macOS v10.14.4.

```
> ~/Code  echo $LDFLAGS
-L/usr/local/opt/zlib/lib
> ~/Code  echo $CPPFLAGS
-I/usr/local/opt/zlib/include
```

Start by inspecting the build log at /var/folders/n3/ws0911_179dfk_rfxwhq6dvr0000gn/T/python-build.20190523131052.99380.log and the ensurepip traceback shown in the issue. Reproduce the macOS installation failure using the reported LDFLAGS and CPPFLAGS, then verify that the installation completes without the zlib import error.

Written by the indexing model from the issue text.