cannot find -lz
```
/usr/bin/ld: cannot find -lz
collect2: error: ld returned 1 exit status
Makefile:941: recipe for target 'cpuminer' failed
make[2]: *** [cpuminer] Error 1
make[2]: Leaving directory '/home/ik/btc-mine/cpuminer-multi'
Makefile:2766: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/ik/btc-mine/cpuminer-multi'
Makefile:585: recipe for target 'all' failed
make: *** [all] Error 2
strip: 'cpuminer': No such file
```
