D24882: Don't set C/C++ standards if already set

[David Faure]

dfaure closed this revision.

REPOSITORY
  R240 Extra CMake Modules

REVISION DETAIL
  https://phabricator.kde.org/D24882

To: dfaure, cgiboudeaux
Cc: kde-frameworks-devel, kde-buildsystem, LeGast00n, GB_2, bencreasy, 
michaelh, ngraham, bruns