Thread stack size issue related to glibc TLS bug

[Martin Buchholz]

Very big picture - if we want to banish stack overflows forever, we would
need to migrate the industry to split runtime stacks, which would add a bit
of runtime overhead to every native function call.  No one is heroic enough
to make progress towards that.  Maybe developers of new OSes need to read
this thread?

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Today, linux kernels run with a variety of libc implementations, so
attempts to use a private glibc symbol might end up looking just like
trying to use a public one, using dlsym at runtime.

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It seems reasonable to switch from _dl_get_tls_static_info
to __pthread_get_minstack.
One strong hint is that glibc uses that when it needs to create its own
helper thread with minimal stack.
But why-oh-why not expose that for use by others?  Other software like Java
or Rust has the same needs!

  /* The helper thread needs only very little resources.  */
  (void) pthread_attr_setstacksize (&attr,
   __pthread_get_minstack (&attr)
   + 4 * PTHREAD_STACK_MIN);