procps_uptime, previously just plain uptime() used to put the
uptime (as a double) in the first argument and return uptime
(as an int).
It meant if you ran
myuptime2 = procps_uptime(&myuptime1, NULL);
You might get different results for myuptime1 and myuptime2 because
they are different types.
Most library calls use the return value to return the status,
procps_uptime was in the middle.
Until now.
This function will return 0 on success. If you want (for whatever
reason) uptime as an int then cast it.
All of the procps binaries didn't use the return value for uptime
except ps which set a variable to it but never used it anywhere.
