[patch] fix build on architectures with a signed size_t

[Florian Weimer]

* Florian Weimer:

> * Matthias Klose:
>
>> attached are three patches to build on architectures with a signed size_t
>> (s390-linux-gnu).
>
> Yuck.  Is this really true?  Seems so.

No, it's not.  At least not in the sid chroot on raptor.debian.org.

FWIW, my corrected test case is:

#include <stdio.h>
volatile size_t x;
main()
{
        x = -1;
        if (x < 0)
                puts("broken");
}