Add C++ bindings for Keystore flags

Test: build
Bug: 369375199
Change-Id: I16162232e5cefdce0ae3a5ad020e83016700b2f8
diff --git a/keystore2/Android.bp b/keystore2/Android.bp
index 4878eb3..92a4bed 100644
--- a/keystore2/Android.bp
+++ b/keystore2/Android.bp
@@ -192,6 +192,11 @@
     defaults: ["framework-minus-apex-aconfig-java-defaults"],
 }
 
+cc_aconfig_library {
+    name: "libkeystore2_flags_cc",
+    aconfig_declarations: "keystore2_flags",
+}
+
 rust_aconfig_library {
     name: "libkeystore2_flags_rust",
     crate_name: "keystore2_flags",