Don't use %z printf format length specified

[Alexander Monakov]

On Wed, 14 Nov 2018, Michael Matz wrote:

> Hi,
> 
> it's not c++98 conforming and I get 1 million warnings when compiling.  
> Initially I had also casts to long at the various arguments, but I get no 
> warning with this variant either, so I removed them again.  I'm currently 
> regstrapping this, okay for trunk if successfull?

Surely this will break mingw-w64 where size_t is 64-bit yet long is 32-bit?

Alexander