Fix integer conversion warnings in hash.c Use unsigned long for temporary variable to avoid integer conversion warnings with UBSan. Note that this does change the computation of hash values for input bytes larger than 0x7F. Before, these bytes were first converted to a (typically) signed char with a negative value, then to a large unsigned long near ULONG_MAX. I doubt that this was intentional. Input bytes larger than 0x7F are now converted to unsigned long unchanged.