ref: 0d7e3fd4a27a8494d8e513b43cac12b7d9b9dea6 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }