aspect.adb, aspect.ads: Added new aspect Secondary_Stack_Size.

aspect.adb, aspect.ads: Added new aspect Secondary_Stack_Size.

2017-01-06  Patrick Bernardi  <bernardi@adacore.com>

	* aspect.adb, aspect.ads: Added new aspect Secondary_Stack_Size.
	* exp_ch3.adb (Build_Init_Statements): As part of initialising
	the value record of a task, set its _Secondary_Stack_Size field
	if present.
	* exp_ch9.adb (Expand_N_Task_Type_Declaration): Create
	a _Secondary_Stack_Size field in the value record of
	the task if a Secondary_Stack_Size rep item is present.
	(Make_Task_Create_Call): Include secondary stack size
	parameter. If No_Secondary_Stack restriction is in place, passes
	stack size of 0.
	* par-prag.adb, sem_prag.adb, sem_prag.ads: Added new pragma
	Secondary_Stack_Size.
	* s-secsta.adb, s-secsta.ads (Minimum_Secondary_Stack_Size): New
	function to define the overhead of the secondary stack.
	* s-tarest.adb (Create_Restricted_Task,
	Create_Restricted_Task_Sequential): Functions now include
	Secondary_Stack_Size parameter to pass to Initialize_ATCB.
	* s-tarest.adb (Create_Restricted_Task,
	Create_Restricted_Task_Sequential): Calls to Initialize_ATCB
	now include Secondary_Stack_Size parameter.
	(Task_Wrapper):
	Secondary stack now allocated to the size specified by the
	Secondary_Stack_Size parameter in the task's ATCB.
	* s-taskin.adb, s-taskin.adb (Common_ATCB, Initialise_ATCB): New
	Secondary_Stack_Size component.
	* s-tassta.adb, s-tassta.ads (Create_Restricted_Task,
	Create_Restricted_Task_Sequential): Function now include
	Secondary_Stack_Size parameter.
	(Task_Wrapper): Secondary stack
	now allocated to the size specified by the Secondary_Stack_Size
	parameter in the task's ATCB.
	* sem_ch13.adb (Analyze_Aspect_Specification): Add support
	for Secondary_Stack_Size aspect, turning the aspect into its
	corresponding internal attribute.
	(Analyze_Attribute_Definition):
	Process Secondary_Stack_Size attribute.
	* snames.adb-tmpl, snames.ads-tmpl: Added names
	Name_Secondary_Stack_Size, Name_uSecondary_Stack_Size,
	Attribute_Secondary_Stack_Size and Pragma_Secondary_Stack_Size.

From-SVN: r244146