utf8_strlen
size = utf8_strlen(c->prompt_buffer);
n = utf8_strlen(c->prompt_saved);
size = utf8_strlen(c->prompt_buffer);
size = utf8_strlen(c->prompt_buffer);
c->prompt_index = utf8_strlen(c->prompt_buffer);
c->prompt_index = utf8_strlen(c->prompt_buffer);
c->prompt_index = utf8_strlen(c->prompt_buffer);
c->prompt_index = utf8_strlen(c->prompt_buffer);
if (utf8_strlen(c->prompt_buffer) != 1)
c->prompt_index = utf8_strlen(c->prompt_buffer);
c->prompt_index = utf8_strlen(c->prompt_buffer);
c->prompt_index = utf8_strlen(c->prompt_buffer);
size_t utf8_strlen(const struct utf8_data *);