AC_HELP_STRING is obsolete, replace with AS_HELP_STRING.
Michael's suggestion to use a statistics_log.wait value of not-zero to
configure statistics logging, that gets rid of the statistics_log.log
boolean.

Make the default timestamp value zero-filled, I want fixed-size columns.
Fix the Python path for EXTRA_INPUT.
Update
pthread_t's are opaque types, don't compare them to integer values.