* alias.h (record_alias_subset): Declare.
	* alias.c (record_alias_subset): Make global.
ada/
	* gcc-interface/decl.c (enum alias_set_op): New enumeration.
	(copy_alias_set): Rename into...
	(relate_alias_sets): ...this.  Add third parameter OP.  Retrieve the
	underlying array of unconstrained arrays for the new type as well.
	If the old and new alias sets don't conflict, make one a subset of
	the other as per the OP parameter.
	(gnat_to_gnu_entity): Adjust calls to copy_alias_set.
	<E_Record_Type>: Do not copy the alias set for derived types.
	For all types, make the alias set of derived types a superset of
	that of their parent type.
	(make_aligning_type): Adjust calls to copy_alias_set.
	(make_packable_type): Likewise.
	* gcc-interface/trans.c (gnat_to_gnu)<N_Validate_Unchecked_Conversion>:
	Check for alias set conflict instead of strict equality to issue the
	warning.

From-SVN: r144084