help: how to "quick rebuild" gcc ?

[DJ Delorie]

> > source files) instead of starting from "make bootstrap" everytime ?
> 
> make -j2 cc1
> is not an uncommon way to do this.  Takes 15 seconds on my machine.

Except it won't do what you expect, because it won't use the stageN
compiler to build stage N+1.  That's what quickstrap and bubblestrap
are for - they know what the bootstrap state is, and use the right
compiler to recompile.