[PATCH 1/2] Replace check_mul_overflow_size_t with INT_MULTIPLY_WRAPV

[Florian Weimer]

* Adhemerval Zanella:

> -  bool overflow = check_mul_overflow_size_t (element_size, count, &size);
> +  bool overflow = INT_MULTIPLY_WRAPV (element_size, count, &size);

What's the reason for not using the compiler built-in?