layout: restructure into src/ tests/ android/ scripts/ tools/

- extension/src/{port,platform,codepage} -> src/; native_render -> src/host
  (+ dxt, shaders/); libgr2 -> src/gr2; extension/third_party -> third_party
- extension/tests -> tests/port, libgr2/tests -> tests/gr2
- android-native -> android (build.sh, push-client.sh moved in)
- script -> scripts; tools/40250 -> tools/server; oracle -> tools/granny-oracle;
  perf tools -> tools/perf
- all build trees under build/ (native, release, android, port-gate)
- xrender:: CMake aliases -> mt::; port-map ledger impl paths rewritten

No code changes. ctest 15/15, port_gate macos+android PASS, port_map check 0 errors.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/platform/ScriptLib/PythonHost.cpp

@@ -0,0 +1,117 @@
+// See PythonHost.h: the interpreter setup 40250 got from a real python27 installation.
+#include "ScriptLib/StdAfx.h"
+#include "PythonHost.h"
+
+#include <cstdio>
+#include <cstdlib>
+
+namespace
+{
+// The pending exception as text, so a failed bootstrap says what went wrong instead of leaving the
+// error for the first unrelated script to trip over.
+std::string take_error()
+{
+	if (!PyErr_Occurred())
+		return "no exception";
+
+	PyObject *type = NULL, *value = NULL, *tb = NULL;
+	PyErr_Fetch(&type, &value, &tb);
+	PyErr_NormalizeException(&type, &value, &tb);
+	std::string text;
+	if (PyObject* str = value ? PyObject_Str(value) : NULL)
+	{
+		if (PyString_Check(str))
+			text = PyString_AS_STRING(str);
+		Py_DECREF(str);
+	}
+	if (type && text.empty())
+		text = ((PyTypeObject*) type)->tp_name;
+	Py_XDECREF(type);
+	Py_XDECREF(value);
+	Py_XDECREF(tb);
+	return text.empty() ? "unknown error" : text;
+}
+
+bool fail(std::string* error, const std::string& text)
+{
+	if (error)
+		*error = text;
+	return false;
+}
+}
+
+namespace PythonHost
+{
+
+void Configure(const char* program_name)
+{
+	// site.py lives in a prefix this interpreter does not have, the environment must not be able to
+	// redirect a game's script layer (PYTHONPATH/PYTHONHOME), the "could not find platform libraries"
+	// probe has nothing to find, and the pack directories are read-only on the mobile targets.
+	Py_NoSiteFlag = 1;
+	Py_IgnoreEnvironmentFlag = 1;
+	Py_FrozenFlag = 1;
+	Py_DontWriteBytecodeFlag = 1;
+	Py_SetProgramName((char*) program_name);
+}
+
+bool InstallStdLib(const char* stdlib_path, std::string* error)
+{
+	if (!Py_IsInitialized())
+		return fail(error, "interpreter is not initialized");
+	if (!stdlib_path || !*stdlib_path)
+		return fail(error, "no stdlib path (set MT_PYTHON_STDLIB or pass python27.zip)");
+
+	// zipimport and the source importer both go through the C library, so the path has to be a real
+	// file: a pack entry or an Android asset must be staged out first (step 3c).
+	if (FILE* fp = fopen(stdlib_path, "rb"))
+		fclose(fp);
+	else if (FILE* dir = fopen((std::string(stdlib_path) + "/os.py").c_str(), "rb"))
+		fclose(dir);
+	else
+		return fail(error, std::string("cannot open ") + stdlib_path);
+
+	PySys_SetPath((char*) stdlib_path);
+
+	// Py_Initialize ran _PyCodecRegistry_Init against the then-empty path and 2.7 never retries it
+	// ("no codec search functions registered" for the rest of the process), so the search function is
+	// registered again now that encodings is importable.
+	PyObject* encodings = PyImport_ImportModule("encodings");
+	if (!encodings)
+		return fail(error, "import encodings: " + take_error());
+	PyObject* search = PyObject_GetAttrString(encodings, (char*) "search_function");
+	Py_DECREF(encodings);
+	if (!search)
+		return fail(error, "encodings.search_function: " + take_error());
+
+	PyObject* codecs = PyImport_ImportModule("codecs");
+	PyObject* registered = codecs ? PyObject_CallMethod(codecs, (char*) "register", (char*) "O", search) : NULL;
+	Py_DECREF(search);
+	Py_XDECREF(codecs);
+	if (!registered)
+		return fail(error, "codecs.register: " + take_error());
+	Py_DECREF(registered);
+	return true;
+}
+
+namespace
+{
+std::string g_staged_path;
+}
+
+void SetDefaultStdLibPath(const char* stdlib_path)
+{
+	g_staged_path = stdlib_path ? stdlib_path : "";
+}
+
+std::string DefaultStdLibPath()
+{
+	// The environment still wins, so a developer can point a build at another stdlib without rebuilding.
+	if (const char* env = getenv("MT_PYTHON_STDLIB"))
+		return env;
+	// Whatever staged the zip for this platform (extension/src/python_stdlib.cpp inside Godot; nothing
+	// in the native tests, which pass the build tree's copy on the command line).
+	return g_staged_path;
+}
+
+}