piggy运行出现UDUnits提示

zys_cdut

我在利用Piggy_Packages-Cygwin64时，输入指令ncrcat 180ma_b1.cam.h0.*-02.nc feb.nc。它提示以下内容：

ncrcat: WARNING NCO was built without UDUnits. NCO is therefore unable to convert values from "days since 0001-01-01 00:00:00" to "days since 0001-01-01 00:00:00". See http://nco.sf.net/nco.html#rbs for more information.
ncrcat: HINT Re-build or re-install NCO enabled with UDUnits.

我应该怎么解决这个警告呢？