/in/foo.c: In function 'Setlnter':
/in/foo.c:23:5: warning: implicit declaration of function 'Unique' [-Wimplicit-function-declaration]
     Unique(c, tmp);
     ^~~~~~
/tmp/ccXQyyBd.o: In function `Setlnter':
foo.c:(.text+0xd1): undefined reference to `Unique'
collect2: error: ld returned 1 exit status