require_relative

VALUE
rb_f_require_relative(VALUE obj, VALUE fname)
{
    VALUE rb_current_realfilepath(void);
    VALUE base = rb_current_realfilepath();
    if (NIL_P(base)) {
        rb_raise(rb_eLoadError, "cannot infer basepath");
    }
    base = rb_file_dirname(base);
    return rb_require_safe(rb_file_absolute_path(fname, base), rb_safe_level());
}