Add unwinder linking to STL setup.

Previously we were bundling this into libc++ and having each binary
resolve its symbols from there. This means that the unwinder that gets
used for a given binary is sensitive to the order in which its
libraries are linked. Making this a static library dependency of each
binary means the right unwinder will always be used.

Bug: 18471342
Bug: 19958712
Change-Id: I782d212784dbf85355b5d9146d7460d675259a0e

core/cxx_stl_setup.mk

@@ -65,6 +65,18 @@ ifneq ($(filter $(my_cxx_stl),libc++ libc++_static),)
         my_ldflags += -nodefaultlibs
         my_ldlibs += -lpthread -lm
         my_ldlibs += $($(my_prefix)$(HOST_OS)_$(my_link_type)_gcclibs)
+    else
+        ifeq (arm,$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
+            my_static_libraries += libunwind_llvm
+        else
+            my_static_libraries += libunwindbacktrace
+        endif
+
+        ifeq ($(my_link_type),static)
+            my_static_libraries += libdl
+        else
+            my_shared_libraries += libdl
+        endif
     endif
 else ifneq ($(filter $(my_cxx_stl),stlport stlport_static),)
     ifndef LOCAL_IS_HOST_MODULE