I want to develop new app on openwrt on ubuntu, which I have already built the firmware on tp-link wr703n. I got a compiled program which is built on windows. Now I have to build a cross compiling environment. I have got the SDK, but when I compiled the program by "make", I got error "platform.h:37:2: error: #error No OS GROUP defined". I rewrite the platform.h, but it's still not working. How to fix it? Or what I did is wrong? Thank you.