CMakeLists: compare wxWidgets and wxPython toolkits

Having wxWidgets and wxPython build using different toolkits leads
to an unusable build. KiCad executables are linked against wxWidgets
shared libraries, which will be in conflict with wxPython ones that
are loaded at runtime. We cannot easily solve it, so at least warn
the users about expected problems.

More information:
https://forum.kicad.info/t/9493
https://bugs.launchpad.net/kicad/+bug/1746753

CMakeLists.txt

@@ -690,6 +690,30 @@ if( KICAD_SCRIPTING OR KICAD_SCRIPTING_MODULES )
 
     #message( STATUS "/ INC_AFTER:${INC_AFTER}" )
 
+
+    # Compare wxPython and wxWidgets toolkits
+    set( _py_cmd "import wx; print(wx.version().split(' ')[1])" )
+
+    # Add user specified Python site package path.
+    if( PYTHON_SITE_PACKAGE_PATH )
+        set( _py_cmd
+            "import sys;sys.path.insert(0, \"${PYTHON_SITE_PACKAGE_PATH}\");${_py_cmd}" )
+    endif()
+
+    execute_process( COMMAND ${PYTHON_EXECUTABLE} -c "${_py_cmd}"
+        RESULT_VARIABLE WXPYTHON_TOOLKIT_RESULT
+        OUTPUT_VARIABLE WXPYTHON_TOOLKIT_FOUND
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+
+    if( NOT wxWidgets_TOOLKIT_FOUND STREQUAL WXPYTHON_TOOLKIT_FOUND )
+        message( FATAL_ERROR "\nwxWidgets and wxPython use different toolkits "
+            "(${wxWidgets_TOOLKIT_FOUND} vs ${WXPYTHON_TOOLKIT_FOUND}). "
+            "It will result in a broken build. Please either install wxPython built using "
+            "${wxWidgets_TOOLKIT_FOUND} or add '-DKICAD_SCRIPTING_WXPYTHON=OFF' to cmake "
+            "parameters to disable wxPython support." )
+    endif()
+
 endif()
 
 if( APPLE )