This macro from lib/isc/include/isc/buffer.h causes a warning on the assignment of _length because `strlen()` returns `size_t`, not `unsigned int`.

#define ISC__BUFFER_PUTSTR(_b, _source) \
    do { \
        unsigned int _length; \
        unsigned char *_cp; \
        _length = strlen(_source); \
        if (ISC_UNLIKELY((_b)->autore)) { \
            isc_buffer_t *_tmp = _b; \
            REQUIRE(isc_buffer_reserve(&_tmp, _length) \
                == ISC_R_SUCCESS); \
        } \
        REQUIRE(isc_buffer_availablelength(_b) >= (unsigned int) _length); \
        _cp = isc_buffer_used(_b); \
        memmove(_cp, (_source), _length); \
        (_b)->used += (_length); \
    } while (0)