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.