instead of PR_Seek, otherwise it won't work on large files. The patch is
contributed by Nils Maier <MaierMan@web.de> and Masatoshi Kimura (:emk)
<VYV03354@nifty.ne.jp>. r=wtc. Thanks to Nils Maier for tracking down the
bug.
git-svn-id: svn://10.0.0.236/trunk@199665 18797224-902f-48f8-a5cc-f745e15eee43