> It seems you analyzed this in more detail, could you
> create a patch also?
This patch appears to work. Only ran on tests coming
with re2c-0.9.10, but
$ diff cnokw.c cnokw.temp
< if((YYLIMIT - YYCURSOR) < 4) YYFILL(4);
> if((YYLIMIT - YYCURSOR) < 5) YYFILL(5);
suggests it is OK. (Other tests show no difference).