TVOUT using NTSC in Arduino Leonardo
Three options.

One, is declaring those 3 variables as global variables in your main file, as valid port + ddr + pin numbers.

Two, declare them as global variables with a 0 value (and don't use the tvout.Tone or tvout.noTone) functions.

Three, edit TVOut.cpp and TVOut.h and remove the tone sections.

Bonus Option, attempt to use the correct procedure by updating the library's definitions. The library had one initial release in 2010 and never got any updates. It's simply not configured for newer atmega chips. See here and here for info on the tvout + leonardo boards, which is entered into the tvout library's hardware_setup.h.

Frankly, if you don't use the Tone function, just declare the variables as 0 and move on.