Deleted `defined()` in ast_common.h around set values.
Deleted `defined()` in ast_common.h around set values.

Some values are defined 0 or 1 at the top of the file. There shouldn't be
a `defined` around these, as the value must the checked, not if they are
defined.

ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz