ref: 6fc8e2e20a7eab5352c7b01660d7e7ea66e716a4 dir: /sys/src/cmd/unix/drawterm/libc/runestrlen.c/
#include <u.h> #include <libc.h> long runestrlen(Rune *s) { return runestrchr(s, 0) - s; }