Generate the known NDK libraries list.

This doesn't need to be manually maintained. It briefly did need to be
during the transition from the old prebuilts, but that's long gone.

Test: treehugger
Bug: http://b/113547923
Change-Id: If05633f3cf622ab39e560a3dfcc88f3eb50406bf
diff --git a/cc/makevars.go b/cc/makevars.go
index 0f9f4c1..4cb414e 100644
--- a/cc/makevars.go
+++ b/cc/makevars.go
@@ -97,7 +97,12 @@
 	ctx.Strict("CLANG_EXTERNAL_CFLAGS", "${config.ClangExternalCflags}")
 	ctx.Strict("GLOBAL_CLANG_CFLAGS_NO_OVERRIDE", "${config.NoOverrideClangGlobalCflags}")
 	ctx.Strict("GLOBAL_CLANG_CPPFLAGS_NO_OVERRIDE", "")
-	ctx.Strict("NDK_PREBUILT_SHARED_LIBRARIES", strings.Join(ndkPrebuiltSharedLibs, " "))
+	ndkLibNames := []string{}
+	for _, lib := range ndkKnownLibs {
+		ndkLibNames = append(ndkLibNames, strings.TrimPrefix(lib, "lib"))
+	}
+	sort.Strings(ndkLibNames)
+	ctx.Strict("NDK_PREBUILT_SHARED_LIBRARIES", strings.Join(ndkLibNames, " "))
 
 	ctx.Strict("BOARD_VNDK_VERSION", ctx.DeviceConfig().VndkVersion())
 
@@ -174,8 +179,8 @@
 	ctx.StrictRaw("SRC_HEADERS", strings.Join(includes, " "))
 	ctx.StrictRaw("SRC_SYSTEM_HEADERS", strings.Join(systemIncludes, " "))
 
-	sort.Strings(ndkMigratedLibs)
-	ctx.Strict("NDK_MIGRATED_LIBS", strings.Join(ndkMigratedLibs, " "))
+	sort.Strings(ndkKnownLibs)
+	ctx.Strict("NDK_MIGRATED_LIBS", strings.Join(ndkKnownLibs, " "))
 
 	hostTargets := ctx.Config().Targets[android.BuildOs]
 	makeVarsToolchain(ctx, "", hostTargets[0])