|Subject:||include_dirs does not take a string as documented.|
include_dirs says it takes a string or an array ref. Internally its only used as an array ref. If you give it a string, it bombs out in process_support_files(). If this never worked I'm perfectly happy with changing the docs so it always takes an array ref and not screw around with special casing a single argument. Otherwise, it should be normalized to an array on input.