This fixes all of the warnings cause by using std::weak_ptr objects when
recursing the symbol inheritance tree to retrieve the root symbol. The
issue is that the weak pointers are not guaranteed to be valid for each
recursion because the lock will go out of scope. Using a std::shared_ptr
object will ensure the lock is valid until it goes out of scope.
This change allows for infinite inheritance depth so internally there is
no limit to deriving library symbols from other derived symbols. Please
note that the Flatten() method now recurses until a symbol with no parent
is found. The user interface is not hooked up at this time.
Jeff Young
Wayne Stambaugh
jean-pierre charras
Jon Evans
Mike Williams
Marek Roszko