layout.adb (Layout_Record_Type): Deal with non-static subtypes of variant records

2006-10-31  Robert Dewar  <dewar@adacore.com>

        * layout.adb (Layout_Record_Type): Deal with non-static subtypes of
        variant records
        (Layout_Variant_Record): Retrieve the discriminants from the entity
	rather than from the type definition, because in the case of a full
	type for a private type we need to take the discriminants from the
	partial view.
        (Layout_Component_List): When applying the Max operator to variants with
        a nonstatic size, check whether either operand is static and scale that
        operand from bits to storage units before applying Max.
	(Layout_Type): In VMS, if a C-convention access type has no explicit
	size clause (and does not inherit one in the case of a derived type),
	then the size is reset to 32 from 64.

From-SVN: r118283