CommonsWare's answer seems like a good idea and I would try that first.
Another approach would be to create an empty integer-list inside your library:
<integer-array name="resources">
</integer-array>
and inside every project list drawables that would be actually used:
<integer-array name="resources">
<item>@drawable/res1</item>
<item>@drawable/res2</item>
<item>@drawable/res3</item>
</integer-array>
This way you have a reference to it inside library and can loop over the list, that will override library's empty list.