ref: 82fb9f8d5093a8ff0cda06c5618d73af4803a3f0 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }