```
./curl/lib/http.c:737:12: warning: unused variable 'result' [-Wunused-variable]
  CURLcode result = CURLE_OK;
           ^
./curl/lib/http.c:1143:12: warning: empty expression statement has no effect; remove unnecessary ';' to silence this warning [-Wextra-semi-stmt]
           ;
           ^
./curl/lib/http.c:995:18: warning: variable 'availp' set but not used [-Wunused-but-set-variable]
  unsigned long *availp;
                 ^
./curl/lib/http.c:996:16: warning: variable 'authp' set but not used [-Wunused-but-set-variable]
  struct auth *authp;
               ^
./curl/lib/http.c:979:12: warning: unused function 'is_valid_auth_separator' [-Wunused-function]
static int is_valid_auth_separator(char ch)
           ^
5 warnings generated.
```

Follow-up to 0d3956b curl#11895
Follow-up to e92edfb curl#11490

Closes #xxxxx