* gcc-interface/decl.c (gnat_to_gnu_entity) <case E_Record_Subtype>:
Tidy up. For a subtype with discriminants and variant part, if a
variant is statically selected and the fields all have a constant
position, put them in order of increasing position. Likewise if
no variant part but representation clause is present.
* gcc-interface/utils.c (make_packable_type): Robustify.
(maybe_pad_type): Use local variable and tidy up condition. If no
alignment is specified, use the original one.
(create_type_stub_decl): Minor tweak.
(convert) <case VECTOR_CST>: Fix typo.
<case CONSTRUCTOR>: Deal with padding types around the same type.
Do not punt on missing fields.
(unchecked_convert): Call finish_record_type to lay out the special
record types made for conversions from/to problematic integer types.
Bump the alignment of CONSTRUCTORs before converting them to a more
aligned type.