Stephen Webb's staging headers patch

[David Edelsohn]

	While most of the file is target word-size dependent, most of it
already seems to be handled by macros like LONG_MAX, etc.  The only
missing piece seems to be that "digits" is not dependent on those values. 

	Might I propose that limits_generic.h remain one file but that the
few remaining pieces which depend on word-size, be made conditional, e.g.

#if LONG_MAX > 2147483647
        static const int digits = 63;
        static const int digits10 = 19;
#else if LONG_MAX > 32767
        static const int digits = 31;
        static const int digits10 = 9;
#else 
        static const int digits = 15;
        static const int digits10 = 4;
#endif

That would avoid multilibbed target includes as well.

Thanks, David