1.0.41.19: runtime: Fix pseudo-atomic on non-x86oid gencgc.

1.0.41.19: runtime: Fix pseudo-atomic on non-x86oid gencgc.

  * Pseudo-atomic is per-thread state, add it to struct thread.

  * Pass the correct pointer for accessing p-a in dynbind.c.

  * In {undo_,}fake_foreign_function_call(), stash reg_ALLOC as
pseudo-atomic-bits on threaded targets.

  * In pseudo-atomic.h, the ppc gencgc code is really non-x86oid
gencgc code.

  * Also in pseudo-atomic.h, update the non-x86oid gencgc code
to do the right thing with threaded pseudo-atomic-bits.

  * Due to the way dynamic binding works on threaded targets, it
is now a requirement that the arch_* pseudo_atomic functions call
the generic versions if foreign_function_call_active_p() is true
on threaded targets (in short, C code needs to be able to enter
pseudo-atomic, not just lisp code).