Something

$ ./waf
[2/2] * cpp_link : default/guitone/src/main.o -> default/guitone/guitone
default/guitone/src/main.o: In function `main':
main.cpp:(.text+0x169): undefined reference to `Guitone::Guitone()'
main.cpp:(.text+0x17a): undefined reference to `Guitone::init()'
collect2: ld returned 1 exit status
Compilation failed