ref: 4c76f46e25f32299c1ed1534c20b5bc65d1a7b7a dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }