ARGH again!?!

Man I thought people knew better.... That thing I mentioned back in please be nice and include everyone happened again! It's a different programmer and a different company this time but, come on! This time the programmer was linking against an external binary C library without a header file but still. If that function ever changes will the .c file forward declaration keep up? I doubt it very much. So its a big time bug waiting to happen. Please please please don't make the mistake this programmer has.