This is version of 3.1.x of at, for running commands at a
specified time. To install, do a

$ ./configure

You might want to change the default maximum load at which batch
jobs are still started by specifying --with-loadavg_mx=... as
argument to configure. The default is 0.8, so that, normally, no
batch job will be started when there's still activity going on.
For an SMP system, you will want to increase this.

Then, do

$ make

and, as root,

# make install

at jobs are run by the atd daemon, which is normally started at boot
time.

Bug reports to:
http://bugs.debian.org/ (Debian bug tracking system)
or
[email protected] (Debian at package maintainers)

If at all possible, I'd appreciate you telling me which version you
found a bug in; run at -V to find out which one.

If you try to use at(1) on a system which does not support setreuid(2),
i.e. if you get an error whch looks vaguely like

undefined symbol _setreuid referenced from text segment

DO NOT try to install at on your system by removing all that strange
PRIV stuff. You will install a rather glaring security hole that way.