Add information to the log file written by 'Do-compile' that allows to calculate the time spent in the various steps.
Add information to the log file written by 'Do-compile' that allows to calculate
the time spent in the various steps.


Build-tools/Do-compile:
  Add information to the log file that allows to calculate the time spent in the
  various steps:
  
  1) Introduce a global variable 'global_step'.
  2) Before each major step, set it to some descriptive value.
  3) Expand the 'log_timestamp()' function to take a parameter (typical: "START",
     "DONE", or "ABORT") and append that to the timestamp in the log file,
     followed by the contents of 'global_step'.
  4) Add the "START" string as parameter to the 'log_timestamp' calls preceding a step.
  5) Add 'log_timestamp("DONE");' calls after the relevant steps.
  6) Add 'log_timestamp("ABORT");' calls to the error exits.

natsys/mariadb_10.2,ollie314/server,slanterns/server,davidl-zend/zenddbi,ollie314/server,ollie314/server,ollie314/server,ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,natsys/mariadb_10.2,davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,flynn1973/mariadb-aix