If you’re trying to build a Python package (in my case, the ReportLab toolkit), and your build fails with a string of error messages starting with Python.h: No such file or directory, the problem is that the package includes some amount of code which is written in C. The build is trying to compile that code, and the C compiler is looking for the Python C headers, and for most Linux users (I ran in to this on an Ubuntu system) the C headers aren’t part of the core Python package. You need the python-dev package. Try this:

sudo apt-get install python-dev

Then try your build again; I bet it will work.