ok finally:
modifying Qt/5.3/clang_64/mkspecs/macx-clang/qmake.conf
this way:
#QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.6
QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.7
did the job.
just in case anybody needs this again. seems easy afterwards -.-
Hi and welcome to devnet,
You should bring this topic on the Qt Creator maling list You'll find there Qt Creator's developers/maintainers (this forum is more user oriented)