@freddix
Use the make file instead of compiling manually, i.e., change to the directory containing the source files, and type:
make
and press enter.
If you really want to do it manually, then type:
gcc -c GLUT-fullscreen.c -o GLUT-fullscreen.o -lGL -lGLUT
Using the make file is much easier. There are compiling instructions on the
basic GLUT template page.
BTW, GLUT full-screen needs the MiniGL header/lib files in order to compile. Those aren't actually available at the moment since they haven't been officially released, and the source repository is down at the moment.
Hans