Revert "Revert "Hide unwinder symbols in each binary.""

Bug: 18471342
Bug: 19958712
This reverts commit 61f675bb53.

Change-Id: I87d3655d1238a9cf26d96dcb0665ba5110931800

core/cxx_stl_setup.mk

@@ -70,6 +70,7 @@ ifneq ($(filter $(my_cxx_stl),libc++ libc++_static),)
     else
         ifeq (arm,$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
             my_static_libraries += libunwind_llvm
+            my_ldflags += -Wl,--exclude-libs,libunwind_llvm.a
         endif
 
         ifeq ($(my_link_type),static)