fix duplicate symbol (examin_sym,stepper_flag)

[d0p1s4m4]

This little patch fix this linker error:

ld.lld: error: duplicate symbol: examin_sym             >>> defined in main.o
>>> defined in edit.o

ld.lld: error: duplicate symbol: stepper_flag           >>> defined in main.oerro
>>> defined in edit.o

ld.lld: error: duplicate symbol: examin_sym
>>> defined in main.oerro                               >>> defined in cell.o```

[sasagawa888]

Thank you.