test: internal functions should be static
test: internal functions should be static

Nothing else uses the object file, but we might as well make our
"private" functions static.

lembacon/tmux-MacOSX-pasteboard,tjt263/tmux-MacOSX-pasteboard,ChrisJohnsen/tmux-MacOSX-pasteboard,bradparks/tmux-MacOSX-pasteboard