Improve r264388 removing namespace pollution previously introduced in
<sys/time.h>. INT64_MAX actually requires __INT64_C() hack to get the
type right on exotic architectures (e.g. on ones with 63-bit ints or long
0x7fffffffffffffff is unsigned int or long). The hardcoded LL suffix is
good enough to avoid these problems for SBT_MAX (it makes the type always
signed long long, without overflow since long long has at least 64 bits).
Many thanks to Bruce Evans for the time spent me to explain this.

Reported by:	bde
Reviewed by:	bde