FIX #1321: problems with accessing the interpreter's Handles

FIX #1321: problems with accessing the interpreter's Handles

I've had to redo the way we turn off buffering and flush the
stdin/stdout/stderr Handles in the dynamically-loaded base package.
Compiling the expression "hSetBuffering stdout NoBuffering" and then
re-using the compiled expression didn't work sometimes (see comments
for details).  Now, I'm explicitly looking up the address the stdout
closure and re-using that.  It should be more robust, if somewhat
unclean.