Patch below adds support for building GDB native on an arm-netbsdelf 
platform.

If there are no objections I'll commit this in a few days.

R.

<date>  Richard Earnshaw  <rearnsha@arm.com>

	* configure.host (arm*-*-netbsdelf*): New host.
	* configure.tgt (arm*-*-netbsdelf*): New target.
	* config/arm/nbsdelf.mh: New file.
	* config/arm/nbsdelf.mt: New file.
	* config/arm/nm-nbsdelf.h: New file.