Exclude libstdc++ from linked libraries.

Also explicitly add libstdc++ includes for necessary targets.

Change-Id: If712ba0ae7908d8147a69e29da5c453a183d6540
diff --git a/libdl/Android.mk b/libdl/Android.mk
index cb1cb7d..448d1b7 100644
--- a/libdl/Android.mk
+++ b/libdl/Android.mk
@@ -23,6 +23,7 @@
 
 LOCAL_SRC_FILES:= libdl.c
 LOCAL_CFLAGS := -Wall -Wextra -Wunused -Werror
+LOCAL_CXX_STL := none
 
 LOCAL_MODULE := libdl
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk