Why are breakpoints caught by the runtime?

[Trass3r via Digitalmars-d]

On Monday, 16 June 2014 at 01:23:28 UTC, Daniel Murphy wrote:
> "Trass3r"  wrote
>> Is there any good reason to catch that?
>> I really want the debugger to fire up.
>
> I know, I hate this.  You can disable it by changing 
> rt_trapExceptions in dmain2.d in druntime to false and 
> rebuilding druntime, which is horrible but what I usually do.  
> Unfortunately it is read before Dmain and the module 
> constructors are run so it's tricky to clear on startup.

So you can't even do something like
extern extern (C) __gshared bool rt_trapExceptions;
void main()
{
	rt_trapExceptions = false;
	asm { int 3; }
}

Strangely enough now my original example triggers the debugger. 
Not a clue what changed.