Useful function declarations

[Shaun Jackman]

> Ok.  Are you willing to put together a patch?  My preference would be a
> symbol that is unlikely to be used by something else like gcc (e.g..
> prefix with __newlib_).  If optional, it should be put in the newlib.h
> header file.

I'd be happy to put the patch together. I'd already started doing this
using __ARM_ARCH_4T__ -- just because the symbol was handy -- so I'll
just fix up the patch to use a more appropriate symbol. My inclination
is to use __newilb_susv3.

Cheers,
Shaun