Use of multiarch is not currently enabled by default on any architecture because of, among other things, an impact on the performance of 'apt-get update'. Users can manually enable multiarch in oneiric by doing the following:

• Create a file /etc/dpkg/dpkg.cfg.d/multiarch containing a line foreign-architecture $arch for the $arch of interest

• If different mirrors are needed for the main arch vs. the foreign arch (e.g., archive.ubuntu.com vs. ports.ubuntu.com), add lines to /etc/apt/sources.list like this:

deb [arch=armel] http://ports.ubuntu.com/ubuntu-ports/ oneiric main

• run apt-get update

• install packages, specifying the architecture as :$arch after the package name:

sudo apt-get install libxext-dev:armel