You should start by installing Macports. Afterwards start a terminal session and run
sudo port install sumo
While this will install a SUMO version you maybe do not want to use, it will pull in all dependencies you need.
If you want to build from a repository checkout you should additionally do
sudo port install automake autoconf
If you wish to use clang rather than gcc for compilation do:
./configure CXX=clang++ CXXFLAGS="-stdlib=libstdc++"
Thanks to all MacOS builders for sharing their insights.