We seem to be mostly installing modules into vendor_perl nowadays.
Make sure that the .debug data from there is captured appropriately.
Also, expand ${PERLLIBDIRS} at the point of assignment so we don't
call the python again and again.
[RP: Fixup to whitespace]
(From OE-Core rev: ed7690bf5cc964b5cee55f5ef13c10c75d8e3463)
Signed-off-by: Phil Blundell <pb@pbcl.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>