bionic, libthread_db x86 fixes

Change-Id: I3be997f5f1f6a894a3c200d4f325cf3bfd428c66
Author: James Rose <james.rose@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
diff --git a/libthread_db/Android.mk b/libthread_db/Android.mk
index 922b9cf..af506ed 100644
--- a/libthread_db/Android.mk
+++ b/libthread_db/Android.mk
@@ -22,12 +22,7 @@
 LOCAL_WHOLE_STATIC_LIBRARIES := libthread_db
 LOCAL_MODULE:=libthread_db
 LOCAL_SHARED_LIBRARIES := libdl libc
-
-# NOTE: Using --no-undefined results in a missing symbol that is defined inside
-# gdbserver and is resolved at runtime. Since there is no library containing
-# this symbol that we can link against, set LOCAL_ALLOW_UNDEFINED_SYMBOLS so
-# that --no-undefined is removed from the linker flags.
-LOCAL_ALLOW_UNDEFINED_SYMBOLS := true
+LOCAL_ALLOW_UNDEFINED_SYMBOLS := false
 LOCAL_SYSTEM_SHARED_LIBRARIES :=
 
 include $(BUILD_SHARED_LIBRARY)