You made me curious about the "#define" versus "if()". And, I asked myself how you write a define with several lines.
In case someone cares, I found this about those defines:
http://www.coker.com.au/russell/ccode/macros.html

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt