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.

lwcc is based on the PCC compiler code. However, the code has been
substantially modified to elminate autoconf, automake, and support for
targets not supported by lwtools.

In addition, many parts have been substantially rewritten to match the
lwtools code style or generally improve readability.

Some source files are substantially similar to the same files from PCC and
retain the original PCC license. Others, containing original or rewritten
code are licensed under the same license as the rest of lwtools.