Is it possible to detect "not defined in header file" ?

[sls1005]

To check if a C macro is defined:
    
    
    let hasNet {.importc: """(
    #ifdef CONFIG_NET
      1
    #else
      0
    #endif
    )""",
      header: "config.h".}: cint
    
    
    Run

To check if `-d:nimNoNetwork` is passed:
    
    
    when defined(nimNoNetwork):
      echo 1
    else:
      echo 2
    
    
    Run