MAME stands for Multiple Arcade Machine Emulator.  When used in conjunction 
with images of the original arcade game's ROM and disk data, MAME attempts 
to reproduce that game as faithfully as possible on a more modern general
purpose computer.  MAME can currently emulate several thousand different 
classic arcade video games from the late 1970s through the modern era.

To build MESS, pass MESS=yes to the script. To build UME pass UME=yes to
the script. To disable building of MAME, pass MAME=no to the script. These
can be combined.