rmm200-- If that's your "second data point", I have to infer that you initially tried to compile the program for the Galileo outside the IDE--something you didn't mention. In that case I understand the problem.
A normal C/C++ program has a main() entry point that the programmer is expected to provide. In Arduino-land it's a little different. Here we write setup() and loop() routines which are called by a hidden main() program that the development environment provides behind the scenes. Something like:
void main()
{
setup();
while (true)
loop();
}
Since you are compiling in an environment that expects a main() you might add that one.
Mikal