cmake HAVE_VISIBILITY_HIDDEN_FLAG examples

Gecode/gecode CMakeLists.txt :206 

check_cxx_compiler_flag(-fvisibility=hidden HAVE_VISIBILITY_HIDDEN_FLAG)

Gecode/gecode contribs/quacode/CMakeLists.txt :126 

check_cxx_compiler_flag(-fvisibility=hidden HAVE_VISIBILITY_HIDDEN_FLAG)