ref: 3c9bfd6f38d8c5dc62c0e176c43f49f283cad311 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }