When building Python 3.2.3 from source on Ubuntu 12.04, the zlib module is not available.

I downloaded the official source distribution from python.org, and attempted to build and install it with the following commands.

tar xfa Python3.2.3.tar.bz2
cd Python-3.2.3
./configure --prefix=/opt/python3.2
make
sudo make install

The make command output includes the following.

Python build finished, but the necessary bits to build these modules were not found:
_curses            _curses_panel      _dbm            
_gdbm              _sqlite3           _ssl            
_tkinter           bz2                readline        
zlib                                            

After running make install and starting the interpreter, the zlib module cannot be imported.

I confirmed that the zlib1g-dev package is installed on my system.

I also found this similar question, which suggests adding the --with-zlib flag to the ./configure command. However, that returns an error that it is an unrecognized option and has no effect.

The solution is to install the Ubuntu package dpkg-dev.

sudo apt-get install dpkg-dev

The reason is explained here.

In short, recent versions of Ubuntu don't store libz.so in the standard /usr/lib location, but rather in a platform specific location. For example, on my system is is in /usr/lib/x86_64-linux-gnu. This prevents Python's build system from finding it.

The dpkg-dev package installs the dpkg-architecture executable, which enables Python to find the necessary libraries.

The original question was about Python 3.2.3. I also downloaded Python 2.7.3 and confirmed that the same problem exists, and this solution is applicable to it as well.