Source fix for Solaris

I know it's been ages since I've done anything to Elfdump, but here's the latest... I have recently updated the source files to include an OS-specifics header. The only advantage this really offers is that now Elfdump will compile on Solaris machines, even with a whole stack of warnings. I have done a test build and run on Solaris 9. I will make version 0.3b source available as soon as I get a chance to test whether the new changes break other systems compatibility.