title: Accessing the value of a Preprocessor Macro definition
body: <p>If I add a macro "FOO=bar" under GCC_PREPROCESSOR_DEFINITIONS (or Preprocessor Macros if you use XCode"), what would be the best way to access the value of "FOO"?</p>
  
  <p>Currently, I use the clumsy:</p>
  
  <pre><code>    #define MACRO_NAME(f) #f
      #define MACRO_VALUE(f)  MACRO_NAME(f)
  
      #ifdef FOO
          NSLog(@"%s", MACRO_VALUE(FOO));
      #else
          NSLog(@"undefined");
      #endif
  </code></pre>
  
  <p>This will output "bar"</p>
  
  <p>Surely, there must be a better/cleaner way?</p>