sem_attr.adb: Implement Machine_Rounding attribute

sem_attr.adb: Implement Machine_Rounding attribute

2005-11-14  Robert Dewar  <dewar@adacore.com>
	    Hristian Kirtchev  <kirtchev@adacore.com>

	* sem_attr.adb: Implement Machine_Rounding attribute
	(Analyze_Access_Attribute): The access attribute may appear within an
	aggregate that has been expanded into a loop.
	(Check_Task_Prefix): Add semantic check for attribute 'Callable and
	'Terminated whenever the prefix is of a task interface class-wide type.
	(Analyze_Attribute): Add semantic check for attribute 'Identity whenever
	the prefix is of a task interface class-wide type.

	* s-vaflop-vms-alpha.adb: Valid_D, Valid_F, Valid_G: Make Val constant
	to avoid warnings.

	* s-fatgen.ads, s-fatgen.adb (Machine_Rounding): New function
	Remove pragma Inline for [Unaligned_]Valid.
	Add comments that Valid routines do not work for Vax_Float

	* exp_attr.adb: Implement Machine_Rounding attribute

	* snames.h: Add entry for Machine_Rounding attribute

From-SVN: r106970