[Patch] Fix ONE_DIRECTION undef warnings.

[Steve Ellcey]

On Wed, 2014-04-30 at 10:56 -0700, Roland McGrath wrote:
> > I agree that fixing this requires mechanical addition of defining
> > ONE_DIRECTION in each converter as part of the API contract with
> > using the skeleton.c file. This is core cleanup work that will bear
> > fruit!
> 
> It may be an indication the the "macro API" needs some more substantial
> cleanup that makes it possible for the users of the API (definers of the
> macros) to be less duplicative of each other.

I was wondering if there was some way to determine the correct value
of ONE_DIRECTION in skeleton.c based on other macros like FROM_DIRECTION
but I didn't see any way to do that.

Steve Ellcey