How to define a preprocessor symbol in Xcode

Question

Is it possible to set a symbol for conditional compilation by setting up properties in an Xcode project?

My aim is to to create a symbol that is available to all fil

Answer 1

It's under "GCC 4.2 Preprocessing" (or just put "prepro" in the search box)...

...however, for the life of me I can't get it to work.

I have my standard Debug and Release configurations, and I want to define DEBUG=1 in the debugging configuration. But after adding it as a value:

(in the settings window) > Preprocessor Macros : DEBUG=1

#if DEBUG
    printf("DEBUG is set!");
#endif 

...never prints/gets called. It's driving me crazy...