[PATCH, ARM] Don't use __thumb2__ to select _REENT_SMALL

[Paul Brook]

On Tuesday 02 June 2009, Richard Earnshaw wrote:
> This cost me at least a couple of hours debugging at the weekend; I was
> trying to work out why my file handles were all corrupted when compiling
> code for Thumb-2.  It turns out that Newlib's config.h was changing the
> ABI depending on the instruction set it was compiling for -- a big No
> No, since code is supposed to interwork freely between the two ISAs!

I'm fairly sure I tested this, and concluded that it had no effect on the 
external library ABI. In fact I think I fixed bugs related to this.
i.e. this only matters if you're trying to compile part of the library as 
Thumb-2 and part as ARM. Do we really care about that? Or did I miss 
something?

Paul