major upgrade to Xtensa port

[Nick Clifton]

Hi Bob,

>> This (huge) patch brings the Xtensa port up to date with Tensilica's 
>> latest binutils code. 

Thanks very much for contributing this code.

> Also, to give appropriate credit, much of the assembler work was done by 
> Sterling Augustine, and the linker work by David Heine.  (Both are 
> Tensilica employees so their work is covered by our copyright assignment.)

You might like to include their names and email addresses in the 
appropriate ChangeLog entries, so they are credited for the work that 
they have done.

> If anyone takes the time to look over these changes, please let me know 
> if you see anything that looks suspicious.  I've been extremely careful 
> in merging these changes, but it would have been easy to mess up.

I did have a look over the patch, but there was nothing glaring that I 
thought might cause problems.  One thing that you might like to consider 
now that this patch has been comitted is to upgrade the xtensa specific 
files (eg: tc-xtensa.c, tc-xtensa.h, elf32-xtensa.c, xtensa-dis.c) to 
ISO C90.

Cheers
   Nick