Problem: Compiler warnings. Crash on startup. (Tony Mechelynck) Solution: Change EMSG2 to EMSGN. Make array one character longer.
Problem: Syntax highlighting can be slow. Solution: Include the NFA regexp engine. Add the 'regexpengine' option to select which one is used. (various authors, including Ken Takata, Andrei Aiordachioaie, Russ Cox, Xiaozhou Liua, Ian Young)