Smartlist index implicitly converted to int

When building with DEBUG_SMARTLIST:

src/common/util.c:4816:45: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int' [-Wshorten-64-to-32]
    const char *s = smartlist_get(env_vars, i);
                    ~~~~~~~~~~~~~           ^
src/common/util.c:4846:54: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int' [-Wshorten-64-to-32]
      const char *s = smartlist_get(env_vars_sorted, i);
                      ~~~~~~~~~~~~~                  ^
2 warnings generated.

src/common/util.c:4816:45: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int' [-Wshorten-64-to-32]
    const char *s = smartlist_get(env_vars, i);
                    ~~~~~~~~~~~~~           ^
src/common/util.c:4846:54: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int' [-Wshorten-64-to-32]
      const char *s = smartlist_get(env_vars_sorted, i);
                      ~~~~~~~~~~~~~                  ^
2 warnings generated.

src/or/control.c:4627:43: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int' [-Wshorten-64-to-32]
    const char *arg = smartlist_get(args, i);
                      ~~~~~~~~~~~~~       ^
1 warning generated.

src/or/geoip.c:153:57: warning: implicit conversion loses integer precision: 'intptr_t' (aka 'long') to 'int' [-Wshorten-64-to-32]
    geoip_country_t *c = smartlist_get(geoip_countries, idx);
                         ~~~~~~~~~~~~~                  ^~~
1 warning generated.

src/or/control.c:4627:43: warning: implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int' [-Wshorten-64-to-32]
    const char *arg = smartlist_get(args, i);
                      ~~~~~~~~~~~~~       ^
1 warning generated.

src/or/geoip.c:153:57: warning: implicit conversion loses integer precision: 'intptr_t' (aka 'long') to 'int' [-Wshorten-64-to-32]
    geoip_country_t *c = smartlist_get(geoip_countries, idx);
                         ~~~~~~~~~~~~~                  ^~~
1 warning generated.