dmd 1.042 and 2.027 releases

[Walter Bright]

bearophile wrote:
> Walter Bright:
>> On Windows, if there are multiple source files on the command line
>> they are now read with a background thread. This may speed up
>> compilation.
> I have tried on Windows, on a 2-core CPU and the CPU usage is about
> 50% still (only one core used). I have not timed much difference in
> compilation times (it's 24 modules).

It's hard to see an overall difference. To see one, I had to compile off 
of an SD card connected via USB.

You'll also not see it in CPU usage, because the I/O thread will be 
paused waiting for the disk.