ENV.to_a

static VALUE
env_to_a(VALUE _)
{
    VALUE ary = rb_ary_new();

    rb_encoding *enc = env_encoding();
    ENV_LOCKING() {
        char **env = GET_ENVIRON(environ);
        while (*env) {
            char *s = strchr(*env, '=');
            if (s) {
                rb_ary_push(ary, rb_assoc_new(env_str_new(*env, s-*env, enc),
                                              env_str_new2(s+1, enc)));
            }
            env++;
        }
        FREE_ENVIRON(environ);
    }

    return ary;
}