building OpenJDK on Ubuntu 7.10

[Jonathan Gibbons]

I'm setting up Ubuntu 7.10 to build JDK, and I'm looking at the info here:
http://hg.openjdk.java.net/jdk7/build/raw-file/tip/README-builds.html

There isn't a section for 7.10, but 7.04 comes pretty close. The only issue
is the xlibs-dev package.  Does anyone have a suggestion on how to fix this?

-- Jon

$ sudo apt-get install xlibs-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package xlibs-dev is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package xlibs-dev has no installation candidate