[PATCH] [BZ 20628] make mallinfo saturating

[Paul Eggert]

On 10/06/2016 09:52 AM, DJ Delorie wrote:
> with a 32-bit memory space none of the values will "happen" to cause an
> overflow, because we never have more than 2^32  bytes of memory or 2^32
> objects to count.

The code should work even when INTERNAL_SIZE_T is 32 bits and size_t is 
64 bits. Although perhaps there are other problems with such 
configurations, we shouldn't make matters worse with this change. For 
example, mallinfo should work if there are multiple 4-GiB arenas in such 
a configuration.