install openssl
install cmake (use brew)
mkdir build
cd build
cmake .. -DLWS_ROLE_WS=1 -DOPENSSL_ROOT_DIR=/usr/local/opt/openssl/ -DOPENSSL_CRYPTO_LIBRARY=/usr/local/opt/openssl/lib/libcrypto.a
make
make install

cd include
sudo cp -r /usr/local/opt/openssl/include/openssl /Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk/usr/include/
sudo cp libwebsockets.h /Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk/usr/include/
sudo cp lws_config.h /Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk/usr/include/
sudo cp -r /usr/local/opt/openssl/include/openssl /Library/Developer/CommandLineTools/SDKs/MacOSX11.1.sdk/usr/include/

Now build the http-server:

cd minimal-examples/http-server/minimal-http-server
rm CMakeCache.txt
cmake .
make

Then run http-server:

./lws-minimal-http-server