Need to exclude libstdc++ for host builds

Change-Id: Ia51a4fdfdbae7377130a43c401c2d8d241671d1e
diff --git a/libcxx.mk b/libcxx.mk
index 1cd2873..5325fd1 100644
--- a/libcxx.mk
+++ b/libcxx.mk
@@ -21,4 +21,7 @@
 	external/libcxxrt/include \
 	$(LOCAL_C_INCLUDES) \
 
+LOCAL_CPPFLAGS += -nostdinc++
+LOCAL_LDFLAGS += -nodefaultlibs
+LOCAL_LDLIBS += -lm -lc
 LOCAL_SHARED_LIBRARIES += libc++