[build] Move unwinder to toplevel libgcc

[Joseph S. Myers]

On Wed, 29 Jun 2011, Paolo Bonzini wrote:

> On 06/20/2011 02:24 PM, Rainer Orth wrote:
> > * The only unwinder-related macro I haven't moved is
> >    LIBGCC2_UNWIND_ATTRIBUTE.  It is only defined gcc/config/mips/mips.h.
> >    I suppose we would need a libgcc equivalent of tm.h for that,
> >    something I didn't want to attack at this point.
> 
> Something like the attached?

This patch appears to create a *second* file called libgcc_tm.h, so there 
is one created in gcc/ and one in libgcc/, which seems incredibly 
confusing.  By all means move the libgcc_tm.h logic to libgcc/ (though 
tm.h will need to continue to include libgcc_tm.h for the target, until 
the transition away from tm.h target macros in target code is complete and 
code includes libgcc_tm.h directly instead), but don't have two headers 
with the same name in different build directories.

I interpreted Rainer's comment as meaning that a 
libgcc/config/mips/mips-lib.h (or similar) file would need to be created 
and inserted in the right place in libgcc_tm_file for the large number of 
targets presently putting mips.h in tm_file.

-- 
Joseph S. Myers
joseph@codesourcery.com