KDE_EXPORT is needed

[Patrick Spendrin]

One issue I have found was that KDE_EXPORT and KDE_IMPORT went missing.

KDE_EXPORT and KDE_IMPORT are needed e.g. if you want to export a
function from a plugin (you never want to import it) meaning that it is
needed for K_EXPORT_PLUGIN to work properly. In that special case we
could use Q_DECL_EXPORT but since we can't always rely on Qt being
available I would prefer if we define those two again.

regards,
Patrick