Fix for PR libgcj/3426:
	* gnu/gcj/convert/natIconv.cc: Include CharConversionException.h,
	errno.h.
	(read): Throw exception if character conversion fails.
	* java/io/BufferedInputStream.java (refill): Now package-private.
	* java/io/InputStreamReader.java (ready): Simplified.
	(refill): New method.
	(read): Use it.

Co-Authored-By: David Brownell <david-b@pacbell.net>

From-SVN: r43975