Fix integer-overflow in dmg_fp::strtod

base/third_party/dmg_fp/dtoa.cc

 /****************************************************************
  *
  * The author of this software is David M. Gay.
  *
  * Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose without fee is hereby granted, provided that this entire notice
  * is included in all copies of any software which is or includes a copy
  * or modification of this software and in all copies of the supporting
@@ skipping 2658 matching lines @@
                                 c = *++s;
                         }
                 if (c >= '0' && c <= '9') {
                         while(c == '0')
                                 c = *++s;
                         if (c > '0' && c <= '9') {
                                 L = c - '0';
                                 s1 = s;
                                 while((c = *++s) >= '0' && c <= '9') {
                                         if (L < (INT_MAX - 10) / 10) {
-                                                L = 10*L + c - '0';
+                                                L = 10*L + (c - '0');
                                         }
                                 }
                                 if (s - s1 > 8 || L > 19999)
                                         /* Avoid confusion from exponents
                                          * so large that e might overflow.
                                          */
                                         e = 19999; /* safe for 16 bit ints */
                                 else
                                         e = (int)L;
                                 if (esign)
@@ skipping 1700 matching lines @@
 #endif
         Bfree(b);
         *s = 0;
         *decpt = k + 1;
         if (rve)
                 *rve = s;
         return s0;
         }
 
 }  // namespace dmg_fp