DMD: Versioning compilation: generate Identifier for each compilation and writeln it.

[BoQsc]

I would like to display some identifier that is set after 
compilation and remains unchanged.
This is to recognise and check if two binaries belong to the same 
compilation or it is a different compilation.


I would place it into **version** command of my program.

This is what I have now.
**Compilation ID** is where I would like to show the identifier.

```
     registerCommand("version", "Show version", { 
writeln("Compilation date: " ~ __DATE__ ~ " " ~ __TIME__ ~ "\n 
Compilation ID: "); });
```