ref: 8e98429e02e837d3e31bcc16e6280c9e6c5c3a24 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }