Merged from trunk 5839:5849

Merged from trunk 5839:5849

For bug #164532, don't rely on ${USERLAND} since the portage tree might
be empty.

For bug #164617, don't change permissions on ${WORKDIR} with unpack().

Use find + xargs to avoid a potential 'Argument list too long' from
bash.  Thanks to solar for reporting.

add some useful options (SpankMan)

try and fix $LastChangedRevision$ (SpankMan)

try and fix $Rev$ (SpankMan)

svn path=/main/branches/prefix/; revision=5850