Unregister pthread_atfork handlers on dlclose()

Bug: http://b/20339788
Change-Id: I874c87faa377645fa9e0752f4fc166d81fd9ef7e
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index cd6709a..dfebdd8 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -25,6 +25,7 @@
     $(LOCAL_PATH)/Android.build.dlopen_check_order_dlsym.mk \
     $(LOCAL_PATH)/Android.build.dlopen_check_order_reloc_siblings.mk \
     $(LOCAL_PATH)/Android.build.dlopen_check_order_reloc_main_executable.mk \
+    $(LOCAL_PATH)/Android.build.pthread_atfork.mk \
     $(LOCAL_PATH)/Android.build.testlib.mk \
     $(LOCAL_PATH)/Android.build.versioned_lib.mk \
     $(TEST_PATH)/Android.build.mk
@@ -204,6 +205,11 @@
 include $(LOCAL_PATH)/Android.build.versioned_lib.mk
 
 # -----------------------------------------------------------------------------
+# Build libraries needed by pthread_atfork tests
+# -----------------------------------------------------------------------------
+include $(LOCAL_PATH)/Android.build.pthread_atfork.mk
+
+# -----------------------------------------------------------------------------
 # Library with dependency loop used by dlfcn tests
 #
 # libtest_with_dependency_loop -> a -> b -> c -> a