I am having the same issue... I can compile fine without using Serial but when I use it I get the message Symbol 'Serial' could not be resolved.
../Main.c:25: error: 'Serial' undeclared (first use in this function)
make: *** [Main.o] Error 1
I have a separate compiled AVR Cross Target Static Library library that my current AVR Cross Target Application is linked to.
HardwareSerial.h is even shown under the includes folder in project explorer.
I have both:
#include <C:\users\Sam\cpp_workspace\AVR_LIB\src\cores\arduino\HardwareSerial.h>
#include <C:\users\Sam\cpp_workspace\AVR_LIB\src\cores\arduino\HardwareSerial.h>
included at the top of my program.
I tried to extern HardwareSerial.h but got an error as well.
Any help would be much apprecieated!
Thanks!