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: Ib5453472a09ebc64818ceb69bcbe1184720ce86a
diff --git a/libdl/Android.bp b/libdl/Android.bp
index 1a5439f..b3f9e97 100644
--- a/libdl/Android.bp
+++ b/libdl/Android.bp
@@ -39,6 +39,7 @@
     recovery_available: true,
     native_bridge_supported: true,
     static_ndk_lib: true,
+    llndk_stubs: "libdl.llndk",
 
     defaults: ["linux_bionic_supported"],
 
@@ -218,7 +219,7 @@
 }
 
 llndk_library {
-    name: "libdl",
+    name: "libdl.llndk",
     native_bridge_supported: true,
     symbol_file: "libdl.map.txt",
 }