I'm OK to include this in the dev guide as long as it is not a first class example of what pythranrc is intended for. So: first an example with another flag, and then something like:

```
By default, you have to install pythran to be able to run it. A trick to ease the development and avoid installing after each change to source is to enable running directly from the source. To this effect you may want to add ``-I<install_prefix>/lib/<python-version>/site-packages/pythran`` to the ``cppflags``.
```

Also if it is just because of NT2, the text should rather be:

```
NT2 is required to compile the C++ code generated by Pythran. It is automatically installed along Pythran. If you don't have NT2 installed in a system directory *and* you try to run Pythran directly from the source directory, the NT2 includes won't be found. A trick to ease the development and to enable running directly from the source is to install Pythran once and to add ``-I<install_prefix>/lib/<python-version>/site-packages/pythran`` to the ``cppflags`` in order to points to the NT2 headers.
```