[Linker error] undefined reference to `LastAttacker' x4
wl_agent.o(.text+0x4b1):wl_agent.cpp: undefined reference to `LastAttacker'
wl_agent.o(.text+0x4b9):wl_agent.cpp: undefined reference to `LastAttacker'
wl_agent.o(.text+0x666):wl_agent.cpp: undefined reference to `LastAttacker'
wl_game.o(.text+0x867):wl_game.cpp: undefined reference to `LastAttacker'
Please help me!