gai_strerror should be #defined in ws2tcpip.h. It is a macro that expands to gai_strerrorA, when the linker still has the name gai_strerror then the compiler didn't include the header file correctly.
Unfortunately your log doesn't show the compiler step, only the linker step. I think the real error is in the compile step (try to delete the net_ip.o file and re-make - I guess there is a warning about the missing header file....)