message: Search explicitly for python3 with new python search
  * This prevents the build from silently trying to use python2. We also require
  development files which were previously optional.
diff: @@ -392,15 +392,18 @@ if(ENABLE_QRENDERDOC OR ENABLE_PYRENDERDOC)
  # Make sure Python 3 is found
  set(Python_ADDITIONAL_VERSIONS 3.9 3.8 3.7 3.6 3.5 3.4)
  if(NOT ${CMAKE_VERSION} VERSION_LESS "3.12")
  - find_package(Python COMPONENTS Interpreter Development)
  - set(PYTHON_EXECUTABLE ${Python_EXECUTABLE})
  - set(PYTHON_LIBRARY ${Python_LIBRARIES})
  - set(PYTHON_INCLUDE_DIR ${Python_INCLUDE_DIRS})
  + find_package(Python3 COMPONENTS Interpreter Development REQUIRED)
  + set(PYTHON_EXECUTABLE ${Python3_EXECUTABLE})
  + set(PYTHON_LIBRARY ${Python3_LIBRARIES})
  + set(PYTHON_INCLUDE_DIR ${Python3_INCLUDE_DIRS})
  else()
  find_package(PythonInterp 3 REQUIRED)
  find_package(PythonLibs 3 REQUIRED)
  endif()
  - # we also need python3-config for swig
  +
  + # we also need python3-config for swig, but it's only for the examples
  + # so it doesn't matter which one we find as long as we find something!
  + # Importantly it doesn't have to match the version we link against
  if(NOT EXISTS "${PYTHON_EXECUTABLE}-config" AND NOT EXISTS "${PYTHON_EXECUTABLE}.${PYTHON_VERSION_MINOR}-config")
  message(FATAL_ERROR "We require ${PYTHON_EXECUTABLE}-config or ${PYTHON_EXECUTABLE}.${PYTHON_VERSION_MINOR}-config to build swig, please install the python dev package for your system.")
  endif()
  