Add argument to TC_LARGEST_EXPONENT_IS_NORMAL

[Nick Clifton]

Hi Richard,

> This patch adds a precision argument to
> TC_LARGEST_EXPONENT_IS_NORMAL so that some formats can be true IEEE
> while others have the variant format.  It also moves the macro's
> documentation into internals.texi.
> 
> Tested on mips64-elf, no regressions.  OK to apply?
> 
> 	* doc/invoke.texi (TC_LARGEST_EXPONENT_IS_NORMAL): Document.
> 	* config/atof-ieee.c (TC_LARGEST_EXPONENT_IS_NORMAL): Add an
> 	argument for the precision.
>         (gen_to_words): Update accordingly.

Approved - please apply.

Cheers
        Nick