Switch from distutils to setuptools/sysconfig (#44)

setup.py

@@ -5,8 +5,8 @@
 import sys
 import contextlib
 from setuptools import Extension, setup, find_packages
-from distutils.command.build_ext import build_ext
-from distutils.sysconfig import get_python_inc
+from setuptools.command.build_ext import build_ext
+from sysconfig import get_path
 from Cython.Build import cythonize
 
 
@@ -76,7 +76,7 @@ def setup_package():
         with io.open(os.path.join(root, "README.md"), encoding="utf8") as f:
             readme = f.read()
 
-        include_dirs = [get_python_inc(plat_specific=True)]
+        include_dirs = [get_path("include")]
 
         ext_modules = []
         for mod_name in MOD_NAMES: