normally we want to use llvm types for constants. but
union constants (which are found inside enums) when
they are initialized with the non-most-aligned-member
must be unnamed structs.

these bubble up to all aggregate types. if a constant of
an aggregate type contains, recursively, a union constant
with a non-most-aligned-member initialized, the aggregate
typed constant must be unnamed too.

this fixes some of the asserts that were coming in from
llvm master branch.