Run $(AR) with LLVMgold.so plugin for CFI targets.

Bug: 34623182
Test: add LOCAL_SANITIZE:=cfi to some static libraries under libstagefright
Change-Id: I4f0d8cbd794e0ce4737c59a4617e93c7a5defec1
diff --git a/core/binary.mk b/core/binary.mk
index 4db3d51..4986c85 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -57,6 +57,7 @@
 my_additional_dependencies := $(LOCAL_ADDITIONAL_DEPENDENCIES)
 my_export_c_include_dirs := $(LOCAL_EXPORT_C_INCLUDE_DIRS)
 my_export_c_include_deps := $(LOCAL_EXPORT_C_INCLUDE_DEPS)
+my_arflags :=
 
 ifneq (,$(strip $(foreach dir,$(subst $(comma),$(space),$(COVERAGE_PATHS)),$(filter $(dir)%,$(LOCAL_PATH)))))
   my_native_coverage := true
@@ -1736,6 +1737,7 @@
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_LDLIBS := $(my_ldlibs)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_TIDY_CHECKS := $(my_tidy_checks)
 $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_TIDY_FLAGS := $(my_tidy_flags)
+$(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_ARFLAGS := $(my_arflags)
 
 # this is really the way to get the files onto the command line instead
 # of using $^, because then LOCAL_ADDITIONAL_DEPENDENCIES doesn't work