Optimize isalpha/digit macros in lexer.
Optimize isalpha/digit macros in lexer.

earthling42/mujs,Frky/mujs,lsm/mujs,ccxvii/mujs,BOGY/mujs,ccxvii/mujs,thurday/mujs,ccxvii/mujs,guiquanz/mujs,evanlabs/mujs,ccxvii/mujs