External model of c28x_serial_ext.slx, could not open source file "termios.h"?

Hi, every one. I'm trying to Build model c28x_serial_ext.slx in External mode, I configure the Data exchange Interface to "External mode", and Transport layer to "serial". (Configuration Parameters->Code Generation->Interface) When I build the model, a fetal error occurs:

    [rtiostream_serial.c]

    "./rtiostream_serial.c", line 45: fatal error: could not open source file "termios.h"

    1 fatal error detected in the compilation of "./rtiostream_serial.c".

    Compilation terminated.

I searched the termios.h file in my computer, and find several files in different directories, for example, C:\Program Files\MATLAB\R2015a\polyspace\verifier\cxx\include\include-libc\bits, C:\ti\ccsv5\tools\compiler\gcc-arm-none-eabi-4_7-2012q4\arm-none-eabi\include, etc. But no one is in the compiler -I paths.

Why this fetal error happens? and How can I resolve it？

Thanks for any help.

shiming