setup.py does not work on osx (`error: command swig failed with exit status 1`)

[davidbp]

Hello,

I've seen the other thread about installation but did not find an answer to my problem.

I can install swig and numpy but when I do python3 setup.py install I get the following

....
running install
running bdist_egg
running egg_info
writing pybolt.egg-info/PKG-INFO
writing dependency_links to pybolt.egg-info/dependency_links.txt
writing requirements to pybolt.egg-info/requires.txt
writing top-level names to pybolt.egg-info/top_level.txt
reading manifest file 'pybolt.egg-info/SOURCES.txt'
writing manifest file 'pybolt.egg-info/SOURCES.txt'
installing library code to build/bdist.macosx-10.9-x86_64/egg
running install_lib
running build_py
creating build/lib.macosx-10.9-x86_64-3.7
creating build/lib.macosx-10.9-x86_64-3.7/bolt
copying python/bolt/bolt.py -> build/lib.macosx-10.9-x86_64-3.7/bolt
copying python/bolt/bolt_api.py -> build/lib.macosx-10.9-x86_64-3.7/bolt
copying python/bolt/__init__.py -> build/lib.macosx-10.9-x86_64-3.7/bolt
copying python/bolt/native.i -> build/lib.macosx-10.9-x86_64-3.7/bolt
running build_ext
building '_bolt' extension
swigging python/bolt/native.i to python/bolt/native_wrap.c
swig -python -o python/bolt/native_wrap.c python/bolt/native.i
python/bolt/config.i:50: Warning 301: class keyword used, but not in C++ mode.
python/bolt/config.i:51: Error: Syntax error - possibly a missing semicolon.
error: command 'swig' failed with exit status 1

It seems swig is not installed but I can do swig -version and I get

SWIG Version 4.0.2

Compiled with clang++ [x86_64-apple-darwin21.1.0]

Configured options: +pcre

Please see http://www.swig.org for reporting bugs and further information