Cross platform support is king for me right now which means Java and Javascript are getting a good run even though I don't much like the languages themselves.
How easy is it to take a D program cross platform? Can it cross compile easily?
The gdc compiler sticks the D front end over gcc, so cross compiling is the same as with gcc/mingw, to the best of my understanding. LDC is another compiler that uses the LLVM backend and it might support cross compiling, I don't know.
Setting up a virtualbox and building from that is pretty easy these days. And you need to test the executables somewhere anyway.
D will be perfectly portable by default, just as with modern C++. If you use the standard library it will compile and run everywhere.