frontend.adb (Frontend): Capture restrictions from config files

2011-11-21  Robert Dewar  <dewar@adacore.com>

	* frontend.adb (Frontend): Capture restrictions from config files
	* lib-load.adb (Load_Unit): Save/set/restore restriction pragma
	information
	* lib-xref.adb (Generate_Reference): Fix handling of obsolescent
	references. This was noticed during debugging, but it is not
	known if it causes real bugs.
	* restrict.ads, restrict.adb: New routines to save/set/restore
	non-partition-wide restrictions.
	* s-rident.ads: Comment changes for new handling of
	No_Elaboration_Code
	* sem.adb (Sem): Save/Set/Restore non-partition-wide restrictions
	* sem_ch10.adb (Analyze_Compilation_Unit): Remove incomplete
	attempt to save/restore non-partition-wide restrictions (now
	this work is all done in Sem).
	* sem_prag.adb (Process_Restrictions_Or_Restriction_Warnings):
	Special handling for restriction No_Elaboration_Code.

2011-11-21  Robert Dewar  <dewar@adacore.com>

	* gnat_ugn.texi: Document new handling of restrictions pragmas.

From-SVN: r181566