install google toolbar on FreeBSD/Firefox

1. fetch http://dl.google.com/firefox/google-toolbar-linux.xpi
2. unzip it
3. edit install.rdf
4. find the line with tag <em:targetPlatform>
5. add one more platform entry: <em:targetPlatform>FreeBSD</em:targetPlatform>
6. save it
7. zip the unzipped files into another .xpi, say google-toolbar-freebsd.xpi
8. drag google-toolbar-freebsd.xpi to firefox window
9. "Install Now"
10. enjoy.