Conditional compilation for debug/release

[Johan Engelen via Digitalmars-d-learn]

How do conditionally compile code for either release ("-release") 
or debug ("-debug")?
Something like this:

version(Debug) {
    pragma(lib, "libcmtd.lib");
} else {
    pragma(lib, "libcmt.lib");
}
In the documentation [1], I don't see any predefined version 
identifiers for this purpose.

Thanks,
  Johan


[1] http://dlang.org/version.html