D22580: Notify users when not using KDE_INSTALL_USE_QT_SYS_PATHS about prefix.sh

[Aleix Pol Gonzalez]

apol marked an inline comment as done.

REPOSITORY
  R240 Extra CMake Modules

REVISION DETAIL
  https://phabricator.kde.org/D22580

To: apol, #frameworks
Cc: albertvaka, kde-frameworks-devel, kde-buildsystem, LeGast00n, sbergeron, 
bencreasy, michaelh, ngraham, bruns