random: Remove RAND_RANGE_BADSCALING (#12374)

This macro is no longer used within php-src since
60ace13, it invokes undefined behavior
depending on the input and the corresponding MT_RAND_PHP mode was deprecated in
PHP 8.3.

Thus remove this macro. Any remaining non-php-src user should just inline it
into their code, but should ideally migrate to a non-biased scaler. In any case
the undefined behavior of the original implementation should be accounted for.

Author: TimWolla

UPGRADING.INTERNALS

@@ -36,6 +36,11 @@ PHP 8.4 INTERNALS UPGRADE NOTES
      instead of int.
    - The macros DOM_NO_ARGS() and DOM_NOT_IMPLEMENTED() have been removed.
 
+ b. ext/random
+   - The macro RAND_RANGE_BADSCALING() has been removed. The implementation
+     should either be inlined and undefined behavior fixed or it should be
+     replaced by a non-biased scaler.
+
 ========================
 4. OpCode changes
 ========================

ext/random/php_random.h

@@ -35,34 +35,6 @@
 
 PHPAPI double php_combined_lcg(void);
 
-/*
- * A bit of tricky math here.  We want to avoid using a modulus because
- * that simply tosses the high-order bits and might skew the distribution
- * of random values over the range.  Instead we map the range directly.
- *
- * We need to map the range from 0...M evenly to the range a...b
- * Let n = the random number and n' = the mapped random number
- *
- * Then we have: n' = a + n(b-a)/M
- *
- * We have a problem here in that only n==M will get mapped to b which
- * means the chances of getting b is much much less than getting any of
- * the other values in the range.  We can fix this by increasing our range
- * artificially and using:
- *
- *               n' = a + n(b-a+1)/M
- *
- * Now we only have a problem if n==M which would cause us to produce a
- * number of b+1 which would be bad.  So we bump M up by one to make sure
- * this will never happen, and the final algorithm looks like this:
- *
- *               n' = a + n(b-a+1)/(M+1)
- *
- * -RL
- */
-# define RAND_RANGE_BADSCALING(__n, __min, __max, __tmax) \
-	(__n) = (__min) + (zend_long) ((double) ( (double) (__max) - (__min) + 1.0) * ((__n) / ((__tmax) + 1.0)))
-
 # ifdef PHP_WIN32
 #  define GENERATE_SEED() (((zend_long) ((zend_ulong) time(NULL) * (zend_ulong) GetCurrentProcessId())) ^ ((zend_long) (1000000.0 * php_combined_lcg())))
 # else