+The distribution that is being prepared or packaged take precedence when
+defining distdefs that were specificly undefined in the inherited
+distribution. This means that if the inherited distribution specificly
+undefines a distdefs but the inheriting distribution (one being prepared
+or packaged) specificly defines it, the distdef will be defined.
+Similarly, if the inherited distribution defines a distdef but the
+inheriting distribution undefines it, the distdef will be undefined.
+Note that, this precedence works only in the top distribution (the one
+being prepared or packaged). If the inherited distribution inherits other
+distributions, all distdefs (defined and specificly undefined) will be
+inherited as is. This means that if one inherited distribution defines a
+distdef that other inherited distribution distdef undefines, it will be
+undefined. However, the top distribution can then override them if
+needed.
+