ref: 69f0d8b299c2d5a61a0f866eed1bf49b9eb08b22 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }