Nim source equivalent to C #define

[geezer9]

Is there a pragma (or some such) that performs like the C preprocessor command: 
    
    
    #define SOMEOPTION
    
    
    Run

I would like definition of some debugging flags to automatically define others. 
For example: 
    
    
    when defined(DEPENDENTFLAG):
         {.define(NEEDEDFLAG).}
    
    
    Run

so that NEEDEDFLAG gets automatically defined even when the nim compille 
command is:
    
    
    nim c -d:DEPENDENTFLAG somesource.nim
    
    
    Run

Thanks