a bit less temporary /tmp

hat-tip to pycuda, i got my ubuntu machine to relax about wiping my temp dir on every reboot:

On Debian (and possibly Ubuntu?), edit the file /etc/default/rcS and change

TMPTIME=0

to the number of days that you'd like to keep files in /tmp around. "30" works for me.

now i won't be so paranoid about installing kernel updates right away.