Re: Speeding up the bootstrap build - a quick hack.

[Stefan Monnier <monnier@iro.umontreal.ca>]

> I don't understand at all what's happening.  Maybe it's something to do
> with compile-zeroth being declared .PHONY.  It also might have to do with
> make somehow regarding *.elc0 as "intermediate files", and is thus "safe"
> to delete them (four times deleted in total).

Maybe it's related to the following part of Make's info:

    Sometimes a file can be made by a sequence of implicit rules.  For
    example, a file 'N.o' could be made from 'N.y' by running first Yacc and
    then 'cc'.  Such a sequence is called a "chain".
    
    [...]
    
       The second difference is that if 'make' _does_ create B in order to
    update something else, it deletes B later on after it is no longer
    needed.  Therefore, an intermediate file which did not exist before
    'make' also does not exist after 'make'.  'make' reports the deletion to
    you by printing a 'rm -f' command showing which file it is deleting.

In that case, I think we can address this with

    .PRECIOUS: $(COMPILE_ZEROTH)


-- Stefan