[cmake] Make sure python headers are treated as system headers

Author: Wentzell

cmake/FindPython.cmake

@@ -146,7 +146,7 @@ ENDFUNCTION(EXEC_PYTHON_SCRIPT)
  # Define python_and_numpy interface target
  add_library(python_and_numpy INTERFACE)
  target_link_libraries(python_and_numpy INTERFACE ${PYTHON_LIBRARY} "${PYTHON_EXTRA_LIBS}")
- target_include_directories(python_and_numpy INTERFACE ${PYTHON_INCLUDE_DIRS} ${PYTHON_NUMPY_INCLUDE_DIR})
+ target_include_directories(python_and_numpy SYSTEM INTERFACE ${PYTHON_INCLUDE_DIRS} ${PYTHON_NUMPY_INCLUDE_DIR})
  target_compile_options(python_and_numpy INTERFACE -Wno-register) # Some version of Python.h still use register
 
  # The C API of numpy has changed with 1.7.0, the macro is a version switch in a few files of the libs.