The test scripts in src/test require python2.
Not sure if this is a build system problem, or a test script problem. Autoconf will pick python, python2, python3 in that order, so the scripts should be probably be written such that they run with either python2 or python3, since systems where python is python3 exist.
PYTHON=python2 ./configure sidesteps the problem on systems where python is python3, but people shouldn't have to do that.
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