Clean up various warnings when building under -Wall Add some gimmicks to prevent fread() and fwrite() warnings about ignoring the return value. Yes, this is probably not a good thing to do, but doing something with a non-success return value is going to involve crashing out or something anyway. Also fix several warnings about variables used while possibly uninitialized. The code flow shows that this cannot be the case but initializing them to a plausible value at declaration time costs pretty much nothing and it makes gcc happy. Also caught a use of | instead of || which probably would have caused a certain check for duplicate declarations in __os9 sections to behave oddly.

The lwbasic directory is an in-progress attempt to write a compiler for a
dialect of basic specifically targetted at the 6809 CPU. It is still
incomplete but is included in this distribution in case someone finds the
code useful. It is not built by default.