Port a benchmark to D?

[Andrej Mitrovic]

Running Ubuntu v10.10 x32 on Virtualbox with hardware virtualization,
GCC v4.4.4 and DMD 2.053 installed.

DMD debug: 54s
DMD optimized: 47s

Google's C++ optimized: 27s (gcc -O3 -lc -lstdc++)
Bear's C++ optimized: 24s (g++ -O3 -std=gnu++0x)

So it's MinGW's fault apparently.