* Do not initialize these variables when initializing the rest of the
thread_locals in the TU; they have unordered initialization so they can be
initialized by themselves.
This fixes a rejects-valid bug: we would make the per-variable initializer
function internal, but put it in a comdat keyed off the variable, resulting
in link errors when the comdat is selected from a different TU (as the per
TU TLS init function tries to call an init function that does not exist).
* On Darwin, when we decide that we're not going to emit a thread wrapper
function at all, demote its linkage to External. Fixes a verifier failure
on explicit instantiation of a thread_local variable on Darwin.
llvm-svn: 291865