check_c_source_compiles(
    "
    #define _XOPEN_SOURCE 500
    #ifdef HAVE_SYS_TYPES_H
    # include <sys/types.h>
    #endif
    #include <sys/socket.h>
    #ifdef HAVE_SYS_UIO_H
    # include <sys/uio.h>
    #endif

    int main(void) {
        #ifdef msg_control
        # error msg_control defined
        #endif

        struct msghdr m;
        m.msg_control = 0;
        return 0;
    }
    "
    HAVE_CONTROL_IN_MSGHDR )