envsetup: add mka function

 - using make command w/ cat function to decypher user's system core count for jobs parameter

derived from drewis @CM

Change-Id: If4ee73d3aceea67a8948e74a81394e85d9559fd6

Conflicts:
	envsetup.sh

Change-Id: If4ee73d3aceea67a8948e74a81394e85d9559fd6
Merge "envsetup: add mka function" into lollipop