I run weechat on gentoo. Gentoo has every software item compiled on the host system via build-scripts.

Every gentoo user has at least one version of python installed as it's the language our package-manager is written in. Many users also have multiple versions of python installed since it's allowed to be slotted.

Now there appears to be a bug in the python-detection system (FindPython.cmake) which exhibits the following, if the main (system) python is set to python-3.2 and in parallel python-2.7 is installed:
cmake . -LA | grep -i python

gives:
PYTHON_EXECUTABLE:FILEPATH=/usr/bin/python
PYTHON_INCLUDE_PATH:PATH=/usr/include/python3.2
PYTHON_LIBRARY:FILEPATH=/usr/lib64/libpython2.7.so

Adding python3.2 in the file FindPython.cmake into lines
NAMES python python2.7 python2.6 python2.5 python2.4 python2.3 python2.2
circumvents the problem, but is not a real solution either.

In my opinion it would be best if weechat could detect (upon compilation or run-time) which python versions are installed, build the plugin against all of them and then choose a suitable one for the script which requests python-support. For now I patched the package for gentoo to use a user-supplied option for compilation.

The respective bug-report can be found here:
https://bugs.gentoo.org/show_bug.cgi?id=426330