Add stub modules for gfxstream emulator compatibility

Android.bp

@@ -4095,3 +4095,26 @@ cc_library_shared {
     srcs: [],
     shared_libs: [],
 }
+
+// Stub modules for gfxstream compatibility (emulator code not used on real hardware)
+cc_defaults {
+    name: "gfxstream_defaults",
+    cflags: [
+        "-DGFXSTREAM_STUB=1",
+    ],
+}
+
+cc_library_static {
+    name: "libgfxstream_backend",
+    srcs: [],
+}
+
+cc_library_static {
+    name: "mesa_gfxstream_guest_iostream",
+    srcs: [],
+}
+
+cc_library_static {
+    name: "mesa_gfxstream_connection_manager",
+    srcs: [],
+}