Not so minor a fix for --enable-targets=all

[Alan Modra]

On Sun, Feb 03, 2013 at 04:32:44PM -0500, Hans-Peter Nilsson wrote:
> > 	* mmo.c (mmo_scan): Clear abfd->symcount.
> 
> ...shouldn't this rather be done in generic code?  Just thinking
> that the backend code should be able to assume the bfd is a
> clean slate and this seems like having to initialize seemingly
> random fields.

Yes.  When I saw the testsuite failures, I assumed mmo was the only
backend needing to zero abfd->symcount, but on looking some more I see
other backends, eg. tekhex, have the same problem.  What's more,
abfd->symcount ought to be preserved.  In fact, every bfd field
changed by an unsuccessful call to a target object_p function ought to
be preserved, except of course those that reflect file
position/caching.  I don't have the time to implement this right now.

-- 
Alan Modra
Australia Development Lab, IBM