Fix kolflib_export
Summary: KOLFLIB_EXPORT Macro causes many linking errors when compiling with craft on windows using mingw and MSVC
Reviewers: KDE Games, cullmann
Reviewed By: cullmann
Subscribers: cullmann, aacid, vonreth, yurchor, kde-games-devel
Differential Revision: https://phabricator.kde.org/D24570