[distcc] using distcc to speed up gcc bootstraps

[Neil Booth]

Alexandre Oliva wrote:-

> > As part of cc1's preprocessed output code.
> 
> But how does it tell that it's time to emit the <directory> directive?

cc1 should be doing the preprocessed output.  Currently it's in
cppmain.c, but it should be moved to a "c-" file in the front end.
This is all part of the work to make cpplib a proper library.
If cc1 is doing the preprocessed output, it's easy for it to dump
whatever it wants in there.

Handling the preprocessed input (with extra lines like yours) is a
little harder, but should be easy once we read a token line at a
time.

Neil.