Examples below are not necessarily in the correct order. See the Remarks section below for more information on the whole process.
An easy way to speed up the process of building and installing the new system is to use more processors to increase the computational power.
To find out what's the number of the processors you have to speed up the process:
sysctl hw.ncpu
For example:
hw.ncpu: 1
Let's set the $NUMBER_OF_PROCESSORS
environmental variable then:
export $NUMBER_OF_PROCESSORS=$(sysctl hw.ncpu | tr -d 'a-z.: ')