implemented in top(1), rather than relying on K&R prototypes, which can
cause problems on targets where there are multiple incompatible calling
conventions and the compiler requires argument information to select the
correct one.
(There's a bit more to do here, since it looks like top(1) also sometimes
provides prototypes for various curses functions rather than relying on
the header file...)
Sponsored by: DARPA, AFRL
MFC after: 1 week
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