Use PyConfig_InitPythonConfig instead of PyConfig_InitIsolatedConfig

Author: Daniel Jacobs

include/pybind11/embed.h

@@ -198,9 +198,11 @@ inline void initialize_interpreter(bool init_signal_handlers = true,
         init_signal_handlers, argc, argv, add_program_dir_to_path);
 #else
     PyConfig config;
-    PyConfig_InitIsolatedConfig(&config);
-    config.isolated = 0;
-    config.use_environment = 1;
+    PyConfig_InitPythonConfig(&config);
+    // Don't parse arguments the way regular python parses command line arguments, because the
+    // arguments will be manually set in initialize_interpreter().
+    config.parse_argv = 0;
+
     config.install_signal_handlers = init_signal_handlers ? 1 : 0;
     initialize_interpreter(&config, argc, argv, add_program_dir_to_path);
 #endif