The default is always UTF-8.

Always write UTF-8 to the log file.

Don't define HAVE_FS_CHARSET, and make GetFSCharset() return "ACP"
instead of "UTF-8".  Ignore the configuration setting, which had no
effect anyway.

Stupid mistake from commit 7cb803ad

Move code from the "vorbis" decoder.

Improve initial seek by not reading/decoding the first frame before
checking for the seek command.