Allow compiling with FB 0.90.1+

This allows FB-Ext to be compiled with FB 0.90.1+. It required further fixes for #if typeof() check issues (similar to 9eb99716aa7107e0e282b4b627beb644bb08e74d) caused by the FB preprocessor changes, and several more fixes for CONSTness regarding memcpy() & co, similar to 416ddf4ac067586407148ddf1d2b88e8658cbd20.

I can successfully build FB-Ext with FB 0.24, 0.90.1, and the latest development version now. That's also why I removed the status.fb901.txt file, as it no longer seems needed now.