CHECK_CXX_SOURCE_COMPILES("
    #include <sys/types.h>
    #include <sys/mman.h>
    int main(){shm_open(0, 0, 0); return 0;}
    " HAVE_SHM_OPEN
)

unset(HAVE_SHM_OPEN CACHE)

check_function_exists(shm_open HAVE_SHM_OPEN)

target_compile_definitions(os_features INTERFACE HAVE_SHM_OPEN)