RFC: -z defs: documentation and reverting

[Nick Clifton]

Hi Guys,

> 	* emultempl/elf32.em (_handle_option): Add support for "-z undefs"
> 	as the opposite of "-z defs".
> 	* ld.texinfo: Document the new option.  Update the description of
> 	the -z defs option to make it clear that it does generate an error
> 	if an undefined symbol reference is found in an object file whilst
> 	creating a shared library.
> 	* NEWS: Document this new feature.

I did not see any objections, so I have gone ahead and checked this patch in.

Cheers
  Nick