diff audioDB.h @ 412:223eda8408e1 api-inversion

Fix the last compiler warning.

Bah.  A 26-line comment to explain a one-line change will not do any
good for the code deletion metric of productivity.  However, I have
learnt something today: specifically, the arithmetic type conversion
rules in C.  Wow.  I had been beginning to think that C programming
wasn't so bad after all: simple, clean semantics, and very little going
on under the hood; nothing there to help the programmer, but nothing
much to actively get in the way.  And then I spend an hour on this.