ref: 3e7ad6ef67711cbf73c61d1ab2d77c82a2ff7b3c dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }