When trying to compile the file ftp.c, I get errors related with
warnings that were marked to be reported as error.
This was the original message:
```
fetch/ftp.c:444:8: error: this statement may fall through [-Werror=implicit-fallthrough=]
type = 'D';
~~~~~^~~~~
fetch/ftp.c:445:2: note: here
case 'D':
^~~~
fetch/ftp.c: In function ‘ftp_request’:
fetch/ftp.c:342:3: error: missed loop optimization, the loop counter may overflow [-Werror=unsafe-loop-optimizations]
for (i = 0; i <= len && i <= end - dst; ++i)
^~~
fetch/ftp.c:342:24: error: missed loop optimization, the loop counter may overflow [-Werror=unsafe-loop-optimizations]
for (i = 0; i <= len && i <= end - dst; ++i)
~~~~~~~~~^~~~~~~~~~~~~~~~~
```