Apply patches from Neil Conway.

Apply patches from Neil Conway.

> Hi Tatsuo,
>
> I've attached a patch for the version of pgbench in CVS. It includes the
> following changes:
>
>     - fix some spelling mistakes, indentation stuff, etc.
>
>     - minor code cleanup -- (void) args instead of (), etc.
>
>     - allocate the state array dynamically, so that it is only as
>     large as needed. This reduces the memory consumption of pgbench
>     slightly, and makes a larger MAXCLIENTS setting possible
>
>     - (the only controversial change) add an option "-l" to log
>     transaction latencies to a file. The "transaction latency"
>     is the time between when the BEGIN is issued and the transaction
>     commits. This is written to a file, along with the client #
>     and the transaction #. The data in the file can then be used
>     for things like:
>
>         - consistency analysis: is the TPS the same through the
>         entire run of pgbench, or does it change?
>
>         - more detailed stats: what is the average latency, worse-case
>         latency, best-case latency?
>
>         - graphs: feed the data to gnuplot, graph latency versus. time
>
>         - etc.
>
>     I was going to store this data in memory and write it to disk
>     at the end of the pgbench run, but that isn't feasible because
>     the data can be very large: for example, ~70MB if benchmarking
>     128 clients doing 100,000 transactions each.
>
> Cheers,
>
> Neil