android: add SDL classes and some engine methods to proguard rules file

android/app/proguard-rules.pro

@@ -1,21 +1,15 @@
-# Add project specific ProGuard rules here.
-# You can control the set of applied configuration files using the
-# proguardFiles setting in build.gradle.
-#
-# For more details, see
-#   http://developer.android.com/guide/developing/tools/proguard.html
+# SDL2 branch (unlike SDL3) doesn't have proguard file
+# As SDL3 migration is planned, which we can easily do it on platforms
+# unsupported by GoldSrc by the way, just prevent whole org.libsdl.app
+# namespace from proguard optimization
+-keep public class org.libsdl.app.* { public static *; }
 
-# If your project uses WebView with JS, uncomment the following
-# and specify the fully qualified class name to the JavaScript interface
-# class:
-#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
-#   public *;
-#}
-
-# Uncomment this to preserve the line number information for
-# debugging stack traces.
-#-keepattributes SourceFile,LineNumberTable
-
-# If you keep the line number information, uncomment this to
-# hide the original source file name.
-#-renamesourcefileattribute SourceFile
+-keep,includedescriptorclasses,allowoptimization class su.xash.engine.XashActivity
+{
+	java.lang.String loadAndroidID();
+	java.lang.String getAndroidID();
+	void saveAndroidID(java.lang.String);
+	java.lang.String getCallingPackage();
+	java.lang.String[] getAssetsList(boolean, java.lang.String);
+	android.content.res.AssetManager getAssets(boolean);
+}