sys_socket [test $HAVE_IOCTL = 0 || test $REPLACE_IOCTL = 1]
errno [test $HAVE_IOCTL = 0 || test $REPLACE_IOCTL = 1]
fd-hook [test $HAVE_IOCTL = 0 || test $REPLACE_IOCTL = 1]
+msvc-nothrow [test $HAVE_IOCTL = 0 || test $REPLACE_IOCTL = 1]
configure.ac:
gl_FUNC_IOCTL