from a 32-bit value to a 64-bit value. This commit does not actually
change anything. It merely provides instructions, scripts, and a safety
measure in Makefile.inc1 for people who want to make the change.
The real change to 64-bit time_t's on sparc64 is scheduled to happen
on March 10th, assuming that so major problems are found between now
and then by early-adopters.
Reviewed by: freebsd-sparc64
