Suppress overflow UB in zend_strtod

Author: nikic

Zend/zend_strtod.c

@@ -2705,7 +2705,7 @@ zend_strtod
 L = c - '0';
 s1 = s;
 while((c = *++s) >= '0' && c <= '9')
-L = 10*L + (c - '0');
+L = (Long) (10*(ULong)L + (c - '0'));
 if (s - s1 > 8 || L > 19999)
 /* Avoid confusion from exponents
  * so large that e might overflow.