D24665: Use ECMGenerateExportHeader to manage deprecated API better

[Friedrich W. H. Kossebau]

kossebau added reviewers: Frameworks, dfaure.

REPOSITORY
  R243 KArchive

REVISION DETAIL
  https://phabricator.kde.org/D24665

To: kossebau, #frameworks, dfaure
Cc: kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns