version.c:17
void
Init_version()
{
    VALUE v = rb_obj_freeze(rb_str_new2(RUBY_VERSION));
    VALUE d = rb_obj_freeze(rb_str_new2(RUBY_RELEASE_DATE));
    VALUE p = rb_obj_freeze(rb_str_new2(RUBY_PLATFORM));

    rb_define_global_const("RUBY_VERSION", v);
    rb_define_global_const("RUBY_RELEASE_DATE", d);
    rb_define_global_const("RUBY_PLATFORM", p);

    /* obsolete constants */
    rb_define_global_const("VERSION", v);
    rb_define_global_const("RELEASE_DATE", d);
    rb_define_global_const("PLATFORM", p);
}
