[Patch] Fix ONE_DIRECTION undef warnings.

[Joseph S. Myers]

On Tue, 29 Apr 2014, Steve Ellcey wrote:

> I think my main issue with this is how many new (duplicate) definitions
> it adds.  This is even more of an issue with something like
> HP_SMALL_TIMING_AVAIL.  Only one platform (alpha) ever sets this to 1.
> But with the current setup, to ensure it always has a value, we have to
> define it to 0 in 9 different hp-timing.h headers.  That replication
> bothers me and I would like to have one default value defined somewhere
> that could be included by the platform specific hp-timing.h files
> instead of defining it in all 9 of the non-alpha hp-timing.h header
> files.  But there doesn't seem to be an existing infrastructure for
> that, and I am not sure if a patch to create such a setup would be
> accepted and I don't know if it should be designed just for hp-timing.h
> or if it should be a more global header file that other platform headers
> could also include to provide default values for other macros.

I don't see a problem with using #include_next in the hp-timing.h case, to 
include generic defaults then override them selectively.

-- 
Joseph S. Myers
joseph@codesourcery.com