Link libc++_static into fs_mgr.

Change-Id: Ic2461d3a30dbd8a22f9800a33fac27c658340b21
diff --git a/fs_mgr/Android.mk b/fs_mgr/Android.mk
index 61bf1ee..1179eaa 100644
--- a/fs_mgr/Android.mk
+++ b/fs_mgr/Android.mk
@@ -35,6 +35,7 @@
 LOCAL_UNSTRIPPED_PATH := $(TARGET_ROOT_OUT_UNSTRIPPED)
 
 LOCAL_STATIC_LIBRARIES := libfs_mgr liblogwrap libcutils liblog libc libmincrypt libext4_utils_static
+LOCAL_CXX_STL := libc++_static
 
 LOCAL_CFLAGS := -Werror