A static LLProcessPtr variable won't be destroyed until after procedural code
has shut down APR. The trouble is that LLProcess's destructor unregisters
itself from APR -- and, for an autokill LLProcess, attempts to kill the child
process. All that is ill-advised after APR shutdown.
Disable use of apr_pool_note_subprocess() mechanism. This should be another
viable way of coping with static autokill LLProcessPtr variables: when the
designated APR pool is cleaned up, APR promises to kill the child process. But
whether it's an APR bug or a calling error, the present (now disabled) call in
LLProcess results in OUR process, the viewer, getting SIGTERM when it asks to
clean up the global APR pool.