Recently in https://www.phoronix.com/scan.php?page=news_item&px=Linux-Pipe-Parallel-Job-Opt I read how GNU Make and 4.3 should speed up kernel builds by up to 10 times.
Since I have a fork GNU make called remake, of that which has hooks for profiling, in addition to other cool things I have updated this to base off of 4.3.
See https://github.com/rocky/remake
One new feature I added recently that I like a lot is the abiity to have remake/make search in parent directories for a Makefile if it is not found in the current directory.