Installing/MacOS Build
Using Homebrew
If you come from a previous macports installation you need to uninstall sumo and fox toolkit first:
sudo port uninstall sumo sudo port uninstall fox
If you did not already install homebrew, do so by invoking
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
make sure your homebrew db is up-to-date
brew update
Install SUMO stable via the SUMO Brew Formula:
brew tap dlr-ts/sumo brew install sumo
After the installation you need to log out/in in order to let X11 start automatically, when calling a gui-based application like "sumo-gui". (Alternatively, you may start X11 manually by pressing cmd-space and entering "XQuartz").
Using Macports (legacy)
This uses a packaged version of sumo which is convenient but may lag behind the latest official release of SUMO.
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
After obtaining the required libraries you can follow the build steps of building under Linux, you might want to add another --prefix=/opt/sumo to the configure line.
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.