Here are my timings for a 1.8 GHz P4:
time ./configure real 0m55.767s user 0m15.590s sys 0m14.530s
time make clean real 0m9.166s user 0m2.980s sys 0m2.270s
time make real 16m55.724s user 11m47.180s sys 1m2.460s
I wonder, if it's really necessary to change configure scripts and do a "configure/make clean all" that often as it's done right now.
The good thing about it is, that it shows how well Linux' mutlitasking does work compared to Windows. You can just let it build it in the background and do other things meanwhile. ;-)