message: Introduced a possible fix for the problem with macOS compiling the C++11 extensions.
diff: +import os
  import platform
  +from distutils.sysconfig import get_config_var
  +from distutils.version import LooseVersion
  from setuptools import setup, find_packages, Extension
  -# On Mac we need to specify that libc++ should be used
  cpp_extra_compile_args = ['-std=c++11']
  +
  +# Taken from the setup.py file in the pandas-library, see the following issue
  +# for more details: https://github.com/pandas-dev/pandas/issues/23424. For mac,
  +# ensure extensions are built for macos 10.9 when compiling on a 10.9 system or
  +# above, overriding distutils behaviour which is to target the version that
  +# python was built for. This may be overridden by setting
  +# MACOSX_DEPLOYMENT_TARGET before calling setup.py
  if platform.system() == "Darwin":
  - cpp_extra_compile_args.append('-stdlib=libc++')
  + if 'MACOSX_DEPLOYMENT_TARGET' not in os.environ:
  + current_system = LooseVersion(platform.mac_ver()[0])
  + python_target = LooseVersion(
  + get_config_var('MACOSX_DEPLOYMENT_TARGET'))
  + if python_target < '10.9' and current_system >= '10.9':
  + os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.9'
  extensions = [
  # The ACSF C++ extension, wrapped with cython
  