merge revision(s) 40208: [Backport #8380]

	* internal.h (MUL_OVERFLOW_SIGNED_INTEGER_P): New macro.
	  (MUL_OVERFLOW_FIXNUM_P): Ditto.
	  (MUL_OVERFLOW_LONG_P): Ditto.

	* array.c (rb_ary_product): Don't overflow on signed integer
	  multiplication.

	* numeric.c (fix_mul): Ditto.
	  (int_pow): Ditto.

	* rational.c (f_imul): Ditto.

	* insns.def (opt_mult): Ditto.

	* thread.c (sleep_timeval): Don't overflow on signed integer addition.

	* bignum.c (rb_int2big): Don't overflow on signed integer negation.
	  (rb_big2ulong): Ditto.
	  (rb_big2long): Ditto.
	  (rb_big2ull): Ditto.
	  (rb_big2ll): Ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40602 b2dd03c8-39d4-4d8f-98ff-823fe69b080e