this moves the creation of "parallel.mk" into a separate shell script instead of bin/tests/system/Makefile. that shell script can now be executed by runall.sh, allowing us to make use of the cygwin "make" command, which supports parallel execution.
this moves the creation of "parallel.mk" into a separate shell script instead of bin/tests/system/Makefile. that shell script can now be executed by runall.sh, allowing us to make use of the cygwin "make" command, which supports parallel execution.