Just to stop the compiler properly instead of erroring out on some ill-formed 
inputs going through the FE down to here.  No functional changes.

Tested on x86_64-suse-linux, applied on the mainline.


2013-03-06  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/trans.c (Attribute_to_gnu): Abort instead of erroring
	out for an unimplemented attribute.


-- 
Eric Botcazou