ref: 8d0d2ec80f06f3d7d8ba44313cd08eaef5d9b5d1 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }