[RFC][PATCH v3] Initial support for C11 Annex K Bounds checking functions

[Roland McGrath]

> It could be, but it's so short that we can just
> put it in each of the affected headers.

We have features.h for exactly this sort of thing.  It boils everything
down to simple __USE_* macros so that individual header files only ever use
"#ifdef __USE_FOO".  There is no reason to depart from that now, and every
reason to continue to avoid #if complexity in individual header files.


Thanks,
Roland