With the 0.208 and 0.209 versions, if I try to launch Breakout (breakout) or Pong revision E (pongf) on my MacBookPro with MacOS 10.13, this error message appears:
Caught unhandled St16invalid_argument exception: Continuation after numeric value ends: 2.52
Found 1 info blocks
Found block with 1 dangling allocations
This error does not occur, using version 0.200.
Launching Pong Doubles (pongd, same driver), the error does not occur using any version.
I asked for help in the MAMEdev forum, and it seems all three games run smoothly without errors in other systems (Windows and Linux).
I installed the pre-compiled versions - downloaded from lngn.net and choccyhobnob.com - because I don't have enough disk space on the MacBookPro to install XCode.
I don't know if I'll find the time to compile MAME using my very old MacPro with MacOS 10.6; I don't even know if it's still possible.
Can someone compile MAME on a new Mac - even waiting for the new version in two weeks - and check if the error persists?