Don't create anonymous namespace

Anonymous namespace is not created separately. When a regular namespace
is created with ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS, that
namespace is used as the anonymous namespace.

Bug: 130388701
Test: CtsBionicTestCases
Change-Id: Ie449a59f303487a7a9ff6fff98e6148e9f968fd2
diff --git a/linker/linker.h b/linker/linker.h
index 782da1c..89390b3 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -165,6 +165,13 @@
    */
   ANDROID_NAMESPACE_TYPE_GREYLIST_ENABLED = 0x08000000,
 
+  /* This flag instructs linker to use this namespace as the anonymous
+   * namespace. There can be only one anonymous namespace in a process. If there
+   * already an anonymous namespace in the process, using this flag when
+   * creating a new namespace causes an error
+   */
+  ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS = 0x10000000,
+
   ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED |
                                            ANDROID_NAMESPACE_TYPE_ISOLATED,
 };