cmake HAVE_SYSTEM examples

InsightSoftwareConsortium/ITK Modules/ThirdParty/MINC/src/libminc/CMakeLists.txt :139 

CHECK_FUNCTION_EXISTS(system   HAVE_SYSTEM)

navit-gps/navit CMakeLists.txt :289 

CHECK_SYMBOL_EXISTS(system stdlib.h HAVE_SYSTEM)

navit-gps/navit CMakeLists.txt :504 

endif(HAVE_SYSTEM)

snl-dakota/dakota src/CMakeLists.txt :170 

check_function_exists(system HAVE_SYSTEM)

snl-dakota/dakota src/CMakeLists.txt :172 

add_definitions("-DHAVE_SYSTEM")

snl-dakota/dakota src/CMakeLists.txt :173 

endif(HAVE_SYSTEM)

aseprite/aseprite third_party/CMakeLists.txt :221 

target_compile_definitions(lualib PRIVATE HAVE_SYSTEM)