fix

setup.py

@@ -74,6 +74,7 @@ _remove_strict_prototype_option_from_distutils_config()
 #openmp_libs=['gomp']
 extra_compile_args=[]
 openmp_libs=[]
+extra_c_compile_args=[]
 extra_cc_compile_args = []
 include_dirs = ['c_utils/', 'libfftpack/', 'libsharp/', 'cxxsupport',
                 'Healpix_cxx', _deferred_pybind11_include(),