The Travis image has various python versions installed in /opt,
none of which have development headers, and they are first in
the PATH. Explicitly use the python in /usr/bin instead.
perl
protobuf-c-compiler
python-dev
perl
protobuf-c-compiler
python-dev
-script: sh build.sh && ./configure && make distcheck
+script: sh build.sh && ./configure --with-python=/usr/bin/python && make distcheck DISTCHECK_CONFIGURE_FLAGS="--with-python=/usr/bin/python"