CMake doesn't detect missing Python.h

Created by: williamfgc

Python-dev is required by PyBind11. Compilation fails even when numpy and mpi4py are installed. This is not detected by cmake.

workspace/ADIOS2/thirdparty/pybind11/pybind11/include/pybind11/detail/common.h:111:20: fatal error: Python.h: No such file or directory
 #include <Python.h>
                    ^
compilation terminated.