Competitive Cross-Platform Development?

Avalonia asks: "I work for a software company in the oil and gas exploration industry with a software development team of seven. Our software and development environment is cross-platform on Solaris, Irix, Linux and Windows. Most of our customers are on Solaris and Irix 64-bit systems, but Linux and Windows are increasingly important. Our environment is based around an elaborate command-line system of Makefiles controlling four different compilers (gcc 3.1, Sun Forte, Irix MIPSpro and Visual C++ 7). Needless to say, maintaining this system and producing modern multi-threaded C++ that will go through the four build systems is time-consuming in the extreme. A large proportion of our time is spent finding C++ code that just works rather than being creative and competitive with new functionality. What tools and strategies can we use to increase our productivity and regain our competitive advantage, without going for Windows only?"

"Our recent single-platform competitors (Windows only) can seriously outrun us in terms of productivity by using a single modern IDE development environment - such as C++ builder or Visual Studio - although we can scale onto larger multiprocessor Unix systems. With Windows 64-bit imminent we may lose our 'big-iron' scalability advantage. Java is not currently an option for the high-performance numerical and immersive graphical aspect of our applications."