The emulator programming legends that make up the MAME team have issued fourth a new version of their eponymous emulator and I have built it for the mac and managed to shoehorn it onto a $35 Raspberry Pi computer, set your expectations accordingly.
There is the usual encyclopaedia of improvements and fixes in the whatsnew. Here is the official announcement about the release and this is the official release page where you can get the Windows build (why would you want that‽), or the source code if you fancy a confused look and a major headache! Visit the Github page to see all the code monkey mutterings.
A macOS build is now available on my MAME page, it was built using the latest High Sierra build and XCode 9.4. There is also a Raspberry Pi version built with Raspbian Stretch, a custom SDL2 and GCC 6.3.