Suppress gcc warning about possibly-uninitialized variable. It's not

Suppress gcc warning about possibly-uninitialized variable.  It's not
clear to me why I'd not seen this message before --- on F-9 it seems to
only happen if Asserts are disabled, which ought to be irrelevant.
Maybe that affects a decision whether to inline get_ten(), which would
be needed to expose the warning condition to the compiler?  Anyway,
the fix is clear.