This patch fixes an issue in the compiler whereby a class-wide allocator
for a type declared within a generic formal package was not treated the
same as a formal type with respect to accessibility checks - leading to
spurious accessibility errors.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* sem_util.adb, sem_util.ads (In_Generic_Formal_Package):
	Created to identify type declarations occurring within generic
	formal packages.
	* sem_res.adb (Resolve_Allocator): Add condition to avoid
	emitting an error for allocators when the type being allocated
	is class-wide and from a generic formal package.