qualifications as unavailable if the union is declared in a system
header
r365985 stopped marking those fields as unavailable, which caused the
union's NonTrivialToPrimitive* bits to be set to true. This patch
restores the behavior prior to r365985, except that users can explicitly
specify the ownership qualification of the field to instruct the
compiler not to mark it as unavailable.
rdar://problem/53420753
Differential Revision: https://reviews.llvm.org/D65256
llvm-svn: 371276