jteeuwen/go-pkg-xmlx — comment on commit 0ecfd7fd9986dc8ad9690d9ef1127645892977ab
File:  line 0
By jteeuwen:

The rune type is part of weekly.2011.10.26.

You do have to build the Go tree with an environment variable to enable it.
It may be a bit premature to use this stuff already, but since Go 1 is coming up and this change will become mandatory, we may as well start using it now.
For info, see the mailing list post: https://groups.google.com/forum/#!searchin/golang-nuts/2011-10-26/golang-nuts/Tsjandv7i0k/2O7b3pRctaAJ