cannot install brotli bindings on Python 2.7 anymore

Hi,

I cannot install brotli from PyPi any more, though seemingly it should still support Python 2.7. I can reproduce by creating a conda environment:

conda create -n py27 python=2.7

Saying `pip install brotli` first tells me to install Visual C++ from http://aka.ms/vcpython27. However, after installing that and trying again, I get the following during compilation:

```
_brotli.obj : warning LNK4197: export 'init_brotli' specified multiple times; using first specification
Creating library bin\temp.win-amd64-2.7\Release\c/common\_brotli.lib and object bin\temp.win-amd64-2.7\Release\c/common\_brotli.exp
encode.obj : error LNK2001: unresolved external symbol _tzcnt_u64
static_dict.obj : error LNK2001: unresolved external symbol _tzcnt_u64
backward_references.obj : error LNK2019: unresolved external symbol _tzcnt_u64 referenced in function FindMatchLengthWithLimit

```

I'm on Windows 10, 64-bit Python. Any hints are appreciated.