[Ada] Storage error on untagged prefixed subprogram calls with -gnatX

[Ada] Storage error on untagged prefixed subprogram calls with -gnatX

gcc/ada/

	* sem_ch3.adb (Analyze_Full_Type_Declaration): If the full type
	has a primitives list but its base type doesn't, set the base
	type's list to the full type's list (covers certain constrained
	cases, such as for arrays).
	(Analyze_Incomplete_Type_Decl): Unconditionally initialize an
	incomplete type's primitives list.
	(Analyze_Subtype_Declaration): Unconditionally set a subtype's
	primitives list to the base type's list, so the lists are
	shared.
	(Build_Derived_Private_Type): Unconditionally initialize a
	derived private type's list to a new empty list.
	(Build_Derived_Record_Type): Unconditionally initialize a
	derived record type's list to a new empty list (now a single
	call for tagged and untagged cases).
	(Derived_Type_Declaration): Unconditionally initialize a derived
	type's list to a new empty list in error cases (when Parent_Type
	is undefined or illegal).
	(Process_Full_View): Unconditionally copy the primitive
	operations from the private view to the full view (rather than
	conditioning it on whether extensions are enabled).
	* sem_ch7.adb (New_Private_Type): Unconditionally initialize an
	untagged private type's primitives list to a new empty list.