Fixes the following issue when compiling using C99:
ext/-test-/rb_call_super_kw/rb_call_super_kw.c
ext/-test-/random/loop.c:16:39: error: extra ';' outside of a function [-Werror,-Wextra-semi]
RB_RANDOM_DEFINE_INIT_INT32_FUNC(loop);
Added `WITH_REAL` versions to `RB_RANDOM_INTERFACE` macros. Also
these macros including "without real" versions no longer contain
the terminator (semicolon and comma).
* random.c: separate abstract rb_random_t and rb_random_mt_t for
Mersenne Twister implementation.
* include/ruby/random.h: the interface for extensions of Random
class.
* DLL imported symbol reference is not constant on Windows.
* check if properly initialized.