Why does libiberty have to build before a C library?

[Nathanael Nerode]

>> Note that any dependencies between modules must be explicitly
>> specified via Makefile dependencies now.  Please do not rely on the
>> order that they're listed - I can pretty much guarantee that that 
>>will NOT work any more.
>
>Right, of course.
>
>Well, I guess I need to figure out where that loop was and whether we
>can break it some other way.  I'd really like libiberty to be built
>after newlib.

My patch *does* that, correctly, via the change from
all-target-libiberty: $(ALL_GCC)
to
all-target-libiberty: $(ALL_GCC_C)

The dependency loop was caused by serialization dependencies, as so:

(explicit)
configure-target-libiberty: all-target-newlib

(normal)
all-target-newlib: configure-target-newlib

(serialization)
configure-target-newlib: configure-target-libiberty

The reordering causes the reordering of the serialization dependencies
so the third dependency doesn't appear.

--
This could still work if cygwin configuration depends on 
libiberty configuration, since we will then have to add an explicit 
dependency such as:

configure-target-winsup: all-target-libiberty

But this is OK; it means that newlib is configured, then built, 
libiberty is configured, then built, and then winsup is configured, 
then built.  (Odd, admittedly.)

But Cygwin doesn't really have a C library to link to until winsup is 
built, so probably the link tests will fail when linking to newlib 
~sans~ winsup.  If they succeed, of course, my above plan would 
actually work.