Add S extensions

Update the tests to ensure it is set on S+ but not otherwise.

Note that the implementation of how the version is derived is still a
placeholder (see b/173188089 for plans).

Bug: 173114427
Test: presubmit (SdkExtensionsTest on R and HEAD)
Merged-In: Ifc46e785a005e12cacb7ad86e8c7798e1d00b37f
Change-Id: Ifc46e785a005e12cacb7ad86e8c7798e1d00b37f
diff --git a/derive_sdk/Android.bp b/derive_sdk/Android.bp
index 85672bd..3e030e8 100644
--- a/derive_sdk/Android.bp
+++ b/derive_sdk/Android.bp
@@ -26,7 +26,10 @@
     shared_libs: ["liblog"],
     // static c++/libbase for smaller size
     stl: "c++_static",
-    static_libs: ["libbase"],
+    static_libs: [
+        "libbase",
+        "libmodules-utils-build",
+    ],
 }
 
 cc_binary {