> sudo apt-get install libgl1-mesa-dev:i386 libgl1-mesa-dev:amd64
Reading package lists... Done
Building dependency tree
Reading state information... Done
libgl1-mesa-dev:i386 is already the newest version.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libgl1-mesa-dev : Depends: mesa-common-dev (= 8.0.2-0ubuntu3) but it is not going to be installed
                   Depends: libxext-dev but it is not going to be installed
                   Conflicts: libgl1-mesa-dev:i386 but 8.0.2-0ubuntu3 is to be installed
 libgl1-mesa-dev:i386 : Conflicts: libgl1-mesa-dev but 8.0.2-0ubuntu3 is to be installed
E: Unable to correct problems, you have held broken packages.