You can optionally tell the build to use the ccache compilation tool. Ccache acts as a compiler cache that can be used to speed up rebuilds. This works very well if you use make clean often, or if you frequently switch between different build products.
cd gedit .bashrc --- At last of bashrc file--- # ccache export USE_CCACHE=1
cd android/roms/los-n (example rom folder) prebuilts/misc/linux-x86/ccache/ccache -M 50G (for linux) prebuilt/linux-x86/ccache/ccache -M 50G (for Mac OS)