according to the spec it may be prefixed, if it is XDG_MENU_PREFIX must
be exported (which matters not to Katana since the main application menu
file is hardcoded anyway). for reference:
https://specifications.freedesktop.org/menu-spec/menu-spec-1.0.html
Signed-off-by: Ivailo Monev <xakepa10@gmail.com>
altought the KIO library is not needed I faced some linking
problems during build, almost as if the libraries requested for
the kded4 building were ignored. this needs further investigation
but for now that will do.
since most of the settings are "frozen" now there is little to no
chance that it will be needed. CMake files that reference paths
for installing .upd files are left intact for now.
