cmake HAVE_CONCURRENCY examples

SsageParuders/Android_Native_Surface my_android_opencv/cmake/OpenCVFindFrameworks.cmake :23 

try_compile(HAVE_CONCURRENCY "${CMAKE_BINARY_DIR}" "${_fname}")

joachimBurket/esp32-opencv cmake/OpenCVFindFrameworks.cmake :23 

try_compile(HAVE_CONCURRENCY "${CMAKE_BINARY_DIR}" "${_fname}")

plumonito/dtslam 3rdparty/opencv-git/cmake/OpenCVFindLibsPerf.cmake :117 

try_compile(HAVE_CONCURRENCY "${CMAKE_BINARY_DIR}" "${_fname}")