Make the connection between implementation and llndk_library explicit

Instead of assuming a module with the .llndk suffix exists, add an
llndk_stubs property to every cc_library module that has a
corresponding llndk_library.  Also rename the llndk_library to have
an explicit .llndk suffix.

Bug: 170784825
Test: no changes to build.ninja (excluding comments) or Android-${TARGET_PRODUCT}.mk
Change-Id: Ic4fa093f126490394909867a08448ed886bc5955
diff --git a/libs/nativewindow/Android.bp b/libs/nativewindow/Android.bp
index 52d73e0..07e5d86 100644
--- a/libs/nativewindow/Android.bp
+++ b/libs/nativewindow/Android.bp
@@ -40,6 +40,7 @@
 
 cc_library {
     name: "libnativewindow",
+    llndk_stubs: "libnativewindow.llndk",
     export_include_dirs: [
         "include",
         "include-private",
@@ -95,7 +96,7 @@
 }
 
 llndk_library {
-    name: "libnativewindow",
+    name: "libnativewindow.llndk",
     symbol_file: "libnativewindow.map.txt",
     unversioned: true,
     export_include_dirs: ["include"],