Work around incorrect dt_needed entries

This applies for apps targeting sdk<=22 and
  only for lp32 platforms.

Bug: http://b/21364029
Change-Id: I903e81c9ccda2a8beaba1d132d68c77d30a4cdb2

linker/dlfcn.cpp

@@ -158,6 +158,8 @@ int dlclose(void* handle) {
 }
 
 void android_set_application_target_sdk_version(uint32_t target) {
+  // lock to avoid modification in the middle of dlopen.
+  ScopedPthreadMutexLocker locker(&g_dl_mutex);
   set_application_target_sdk_version(target);
 }