I just checked mine over here.. Ive had 2.0.8 installed since the end of June (thats the date my DMG was downloaded anyways) and have built every version of MAME since June 27th with it (including 0.203 the other day). Including the latest, thats 6 (Im guessing I updated SDL2 in June on MAME release day since it was the 27th). Running 10.13.6 here so you can rule that out along with SDL2.