Adding this answer partially because it fixed my problem of the same issue and so I can bookmark this question myself.

I was able to fix it by doing the following:

sudo apt-get install gcc-multilib g++-multilib

If you've installed a version of gcc / g++ that doesn't ship by default (such as g++-4.8 on lucid) you'll want to match the version as well:

sudo apt-get install gcc-4.8-multilib g++-4.8-multilib

It does look like a cross-platform compilation issue. Did you install the multilib packages:

sudo apt install gcc-multilib g++-multilib

If you've installed a version of gcc / g++ that doesn't ship by default you'll want to match the version as well:

sudo apt-get install gcc-4.8-multilib g++-4.8-multilib

Related question.

The 64-bit bits/c++config.h file is provided on 32-bit systems (and vice-versa) by installing the g++-multilib package, so you need to install that package either using Software Center, Synaptic, or via the terminal using

sudo apt-get install g++-multilib

This is just a dependency package that resolves to g++-4.8-multilib for the default gcc/g++ version, and in turn depends on lib64stdc++-4.8-dev (64-bit compilation on 32-bit) or libx32stdc++-4.8-dev (32-bit compilation on 64-bit) - it is these that contain the actual header files.

There is an equivalent set of packages for the plain C compiler gcc.