GNU make fork with improved error reporting and debugging

 Modernized version of GNU make utility that adds improved error
 reporting, the ability to trace execution in a comprehensible way, and
 a debugger. Some of the features of the debugger are:
  * see the target call stack
  * set breakpoints on targets
  * show and set variables
  * execute arbitrary "make" code
  * issue shell commands while stopped in the middle of execution
  * inspect target descriptions
  * write a file with the commands of the target expanded