ref: 51496e8b8d5cae9f74e07f43ad8cc6b893fc7a19 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }