Re: RfC: Don't cd into subdirs during kbuild

[Peter Samuelson <peter@cadcamlab.org>]

[Xavier Bestel]
> > make -f subdir/Makefile
> 
> Could you do instead:
> 
>         include subdir/Makefile
> ?

Unfortunately, no.  Not without changing the entire architecture of
the kernel build system.  The current system depends on each Makefile
maintaining an independent state (think "stack frame") by means of a
lot of local variables.  These variables have standard names and
functions, so you can't flatten the recursion without clobbering them.

> This would avoid recursive make, which isn't really a good idea
> (even if it's used widely).

Yes, we know recursive make is considered harmful - that's why Keith
Owens designed a nonrecursive solution last year.  (And quite a nice
piece of work it was, too.)  But to achieve his solution he basically
redesigned the whole system from scratch.  Pretty much the *only*
thing kbuild2.5 has in common with current kbuild is a minimal set of
functional requirements.

Peter