mothra not respecting charset=utf-8

[Ethan Grammatikidis <eekee57@fastmail.fm>]

i just ran into a little problem because http's default encoding is
iso-8859-1. i modified rc-httpd to correct it like this:

type = `{echo $full_path | awk -f $libdir/quickfile.awk}
if(~ $"type text/plain) {
	type = 'text/plain; charset=utf-8'
}

in firefox this worked fine, but mothra still loads the file as if it
were iso-8859-1. here's the file; the problem characters are the degree
signs near the end of several lines:

http://ethan.uk.to/static/awk-stew/sensors_compact