einfo.adb (Has_Pragma_Unused): Create this function as a setter for a new flag294 (Set_Has_Pragma_Unused):...

2016-07-04  Justin Squirek  <squirek@adacore.com>

	* einfo.adb (Has_Pragma_Unused): Create this function as a setter
	for a new flag294 (Set_Has_Pragma_Unused): Create this procedure
	as a getter for flag294 (Write_Entity_Flags): Register the new
	flag with an alias
	* einfo.ads Add comment documenting Has_Pragma_Unused (flag294)
	and subsequent getter and setter declarations.
	* lib-xref.adb (Generate_Reference): Recognize Has_Pragma_Unused
	flag to print appropriate warning messages.
	* par-prag.adb (Prag): Classify Pragma_Unused into "All Other
	Pragmas."
	* snames.ads-tmpl Add a new name to the name constants and a
	new pramga to Pragma_Id for pramga Unused.
	* sem_prag.adb (Analyze_Pragma): Create case for Pragma_Unused
	and move the block for Pragma_Unmodified and Pragma_Unreferenced
	out and into local subprograms.
	(Analyze_Unmodified, Analyze_Unreferenced): From the old pragma blocks
	that have been separated in to local subprograms add a parameter to
	indicate the if they are being called in the context of Pragma_Unused
	and handle it accordingly.
	(Is_Non_Significant_Pragma_Reference): Add an entry for Pragma_Unused
	and correct the position of Pragma_Unevaluated_Use_Of_Old.
	* sem_util.adb (Note_Possible_Modification): Recognize
	Has_Pragma_Unused flag to print appropriate warning messages.

From-SVN: r237961