cmake HAVE_POPEN examples

MiKTeX/miktex CMakeLists.txt :1332 

check_function_exists(popen HAVE_POPEN)

navit-gps/navit CMakeLists.txt :845 

CHECK_FUNCTION_EXISTS (popen HAVE_POPEN)

InsightSoftwareConsortium/ITK Modules/ThirdParty/MINC/src/libminc/CMakeLists.txt :130 

CHECK_FUNCTION_EXISTS(popen    HAVE_POPEN)

danigm/poppler ConfigureChecks.cmake :33 

check_function_exists(popen HAVE_POPEN)

rbfx/rbfx Source/ThirdParty/swig/CMakeLists.txt :35 

check_function_exists(popen HAVE_POPEN)