print/cups-filters and compile errors with qpdf

[Naram Qashat]

I just wanted to send this out to the list because this has bitten a few 
people already. If you get a compile error in relation to qpdf.h 
missing, this is because print/qpdf needs to be built with the SDK 
option enabled. The option is defaulted, but it wasn't always the case, 
so if you use ports, just rebuild with that option enabled, if you use 
packages, just get the latest package.

Thanks,
Naram Qashat