So we only need one copy in the final library, not one copy per time
used. Ensure all necessary includes are in place (especially to get the
right size of off_t each time it is compiled) by including "config.h" in
the new graph.c.
One small adjustment here makes the graph_free code more robust- ensure
we don't have invalid pointers after each iteration by looking at the
parents and children and adjusting accordingly.
Signed-off-by: Dan McGee <dan@archlinux.org>
