make newer MSCV7 compilers use _strtoi64() as a strtoll() replacement

#if SIZEOF_CURL_OFF_T > 4

#if HAVE_STRTOLL

#define strtoofft strtoll

#else

#else /* HAVE_STRTOLL */

/* For MSVC7 we can use _strtoi64() which seems to be a strtoll() clone */

#if defined(_MSC_VER) && (_MSC_VER >= 1300)

#define strtoll _strtoi64

#else /* MSVC7 or later */

curl_off_t curlx_strtoll(const char *nptr, char **endptr, int base);

#define strtoofft curlx_strtoll

#define NEED_CURL_STRTOLL

#endif

#else

#endif /* MSVC7 or later */

#endif /* HAVE_STRTOLL */

#else /* SIZEOF_CURL_OFF_T > 4 */

/* simply use strtol() to get 32bit numbers */

#define strtoofft strtol

#endif