[moved from email]

I noticed that the file "serial.c" is missing the include for <avr/signal.h>. Once I add this, the source compiles cleanly...

Thanks for the information.

Are you using the latest WinAVR build? I think with older builds the include is required, but with newer builds it is not. I have just tried a clean build and everything seems to build with no errors or warnings.

Regards.