D14112: Fix CMakeLists.txt to work with older versions of CMake

[Aleix Pol Gonzalez]

apol added a comment.


  uh? isn't that the same?

REPOSITORY
  R134 Discover Software Store

REVISION DETAIL
  https://phabricator.kde.org/D14112

To: ngraham, apol, #discover_software_store
Cc: plasma-devel, ragreen, Pitel, ZrenBot, lesliezhai, ali-mohamed, 
jensreuterberg, abetts, sebas, apol, mart