unwind failures due to __pthread_initialize_minimal

[David Mosberger]

I'm seeing unwind errors because __pthread_initialize_minimal is being
called through the init-section rather than the init_array mechanism.
Is there a reason why nptl/sysdeps/pthread/pt-initfini.c can't be
re-written to use the constructor/destructor attributes instead?  That
would do the right thing on each platform (i.e., use .init/.fini where
necessary and .init_array/.fini_array where available).  If there is
nothing that prevents this, I'd be willing to create the necessary
patch.

	--david