cmake HAVE_IOS examples

FreeCAD/FreeCAD cMake/ConfigureChecks.cmake :19 

check_include_file_cxx(ios HAVE_IOS)

plumonito/dtslam 3rdparty/opencv-git/modules/imgcodecs/CMakeLists.txt :84 

add_definitions(-DHAVE_IOS=1)

plumonito/dtslam 3rdparty/opencv-git/modules/videoio/CMakeLists.txt :157 

add_definitions(-DHAVE_IOS=1)