android-native: SDL3 APK build for the native client

build-android-native.sh downloads SDL 3.4.16 (sha256-checked), builds
libSDL3.so and libmain.so (native_render + port_platform + embedded
Python) at API 24, and wraps them in the SDLActivity shell under
android-native/ (package org.metin2port.client). push-android-client.sh
copies the 40250 Client directory into the app's files/ with run-as
(--locale XX selects locale_XX.cfg). port_logic links with
--no-dependent-libraries on ELF targets so the verbatim
`#pragma comment(lib, ...)` lines do not break lld.

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

native_render/README.md

@@ -32,21 +32,28 @@ returned by SDL's `SDL_GetBasePath`). `MT_PYTHON_STDLIB` can override the zip pa
 
 ## Android integration
 
-With an Android toolchain and SDL3 Android AAR/Prefab available to CMake, the
-same option builds `libmain.so` for SDLActivity. The `mt_native_android_assets`
-target prepares `native.vert.spv`, `native.frag.spv`, and `python27.zip` under
-`<build>/native_render/android-assets` (`python27.zip` is included when the
-embedded Python target is enabled); include that directory in the SDL app's
-`assets.srcDirs`. The app must allow network access for login. The 40250 `Client`
-directory must be placed at `SDL_GetPrefPath("mtgodot", "native-render")/Client`,
-with `pack/Index` present, before live mode starts. The Godot APK is a separate
-application and does not launch this SDL renderer.
+`./build-android-native.sh [Debug|Release] [--install]` builds the arm64 APK
+(`android-native/app/build/outputs/apk/debug/app-debug.apk`, package
+`org.metin2port.client`): it downloads SDL 3.4.16 (sha256-checked) into
+`build-android-native/_deps`, builds `libSDL3.so`, cross-builds `libmain.so`
+(this target + `port_platform` + embedded Python) at API 24, and wraps both in the
+SDLActivity shell under `android-native/` (`MainActivity` passes the launch intent's
+`args` extra as argv). `mt_native_android_assets` supplies `native.vert.spv`,
+`native.frag.spv` and `python27.zip` as APK assets.
 
-The standalone `arm64-v8a` renderer cross-builds at Android API 24. The full
-live-client cross-build currently stops in `extension/src/port/common/Win32Crt.cpp`:
-the NDK exposes `<iconv.h>` at API 24 but does not declare `iconv` until API 28.
-This is a port-runtime prerequisite for an Android live-client APK; raising the
-minimum API level is not assumed here.
+The 40250 `Client` directory is not packaged. `./push-android-client.sh` copies it
+to the app's `files/Client` (`SDL_GetPrefPath`) with `run-as`, so it needs the
+debug-signed APK installed first. Without arguments the app runs against the
+in-process fake server; for a real server:
+
+```sh
+adb shell am start -n org.metin2port.client/.MainActivity \
+    --es args "--live-server HOST:AUTH_PORT:GAME_PORT --login-screen"
+```
+
+Code page conversion does not use iconv: `extension/src/codepage` carries Microsoft's
+WindowsBestFit tables for 874/932/936/949/950/1250-1258 (regenerate with
+`python3 script/gen_codepage_tables.py`), so Android converts the same as macOS.
 
 The Vulkan portability enumeration extension is selected only when advertised
 by the loader. DDS, TGA, and memory textures retain their existing decoders;