Differentiating between 0.24 and 0.25

[Bastian Mezurashii]

Is there any way to differentiate between GDC 0.24 and 0.25?

I am writing a library binding that needs siginfo_t, this is defined in 
gcc.configunix in 0.24 and gcc.config.unix in 0.25.

Is there a built in Version that I can use or would I have to define my 
own?

e.g.

version (GNU)
{
  version (Unix) 
  {
    version (OldGDC)
    {
      public import gcc.configunix;
    }
    version (NewGDC)
    {
      public import gcc.config.unix;
    }
  }
}