Missing include "bits/c++config.h" when cross compiling 64 bit program on 32 bit in Ubuntu

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

Did you try adding -I/usr/include/c++/4.4/i486-linux-gnu or -I/usr/include/c++/4.4/i686-linux-gnu?

While compiling in RHEL 6.2 (x86_64), I installed both 32bit and 64bit libstdc++-dev packages, but I had the "c++config.h no such file or directory" problem.

Resolution:

The directory /usr/include/c++/4.4.6/x86_64-redhat-linux was missing.

I did the following:

cd /usr/include/c++/4.4.6/
mkdir x86_64-redhat-linux
cd x86_64-redhat-linux
ln -s ../i686-redhat-linux 32

I'm now able to compile 32bit binaries on a 64bit OS.