MSVC: don't set python home when running from build dir

This allows you to specify your python home via the
environment and get a working python setup when running
in-place.

pcbnew/swig/python_scripting.cpp

@@ -179,7 +179,10 @@ bool pcbnewInitPythonScripting( const char* aStockScriptingPath, const char* aUs
     pyHome.Normalize();
 
     // MUST be called before Py_Initialize so it will to create valid default lib paths
+    if( !wxGetEnv( wxT( "KICAD_RUN_FROM_BUILD_DIR" ), nullptr ) )
+    {
         Py_SetPythonHome( pyHome.GetFullPath().c_str() );
+    }
 #endif
 
     Py_Initialize();