ref: bfb64acc57c5d88b9d8de7f80edae9e66e0d0dea dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }