par-ch12.adb: Grammar update and cleanup.

2006-10-31  Hristian Kirtchev  <kirtchev@adacore.com>
	    Javier Miranda  <miranda@adacore.com>

	* par-ch12.adb: Grammar update and cleanup.
	(P_Formal_Type_Definition, P_Formal_Derived_Type_Definition): Add
	support for synchronized derived type definitions.
	Add the new actual Abstract_Present to every call to
	P_Interface_Type_Definition.
	(P_Formal_Object_Declarations): Update grammar rules. Handle parsing of
	a formal object declaration with an access definition or a subtype mark
	with a null exclusion.
	(P_Generic_Association): Handle association with box, and others_choice
	with box, to support Ada 2005 partially parametrized formal packages.

From-SVN: r118289